0001171843-21-001411 | 10-K | XBRL Viewer | Biocryst Pharmaceuticals INC

Significant Accounting Policies [Text Block]

Note 1 — Significant Accounting Policies and Concentrations of Risk

The Company

BioCryst Pharmaceuticals, Inc. (the “Company”) is a commercial-stage biotechnology company that discovers novel, oral, small-molecule medicines. The Company focuses on the treatment of rare diseases in which significant unmet medical needs exist and an enzyme plays the key role in the biological pathway of the disease. The Company was founded in 1986 and incorporated in Delaware in 1991, and its headquarters is located in Durham, North Carolina. The Company integrates the disciplines of biology, crystallography, medicinal chemistry and computer modeling to discover and develop small molecule pharmaceuticals through the process known as structure-guided drug design. The Company has incurred losses and negative cash flows from operations since inception.

Based on the Company’s expectations for revenue, operating expenses, and its option to access an additional $75 million from its existing credit facility, the Company believes its financial resources available at December 31, 2020 will be sufficient to fund its operations into 2023. The Company has sustained operating losses for the majority of its corporate history and expects that its 2021 expenses will exceed its 2021 revenues. The Company expects to continue to incur operating losses and negative cash flows until revenues reach a level sufficient to support ongoing operations. The Company’s liquidity needs will be largely determined by the success of operations in regard to the successful commercialization of its products and the progression of its product candidates in the future. The Company also may consider other plans to fund future operations, including: (1) securing or increasing U.S. Government funding of its programs, including obtaining procurement contracts; (2) out-licensing rights to certain of its products or product candidates, pursuant to which the Company would receive cash milestones; (3) raising additional capital through equity or debt financings or from other sources, including royalty or other monetization transactions; (4) obtaining additional product candidate regulatory approvals, which would generate revenue, milestones and cash flow; (5) reducing spending on one or more research and development programs, including by discontinuing development; and/or (6) restructuring operations to change its overhead structure. The Company may issue securities, including common stock, preferred stock, depositary shares, purchase contracts, warrants, debt securities and units, through private placement transactions or registered public offerings in the future. The Company’s future liquidity needs, and ability to address those needs, will largely be determined by the success of its products and product candidates, timing, scope and magnitude of its commercial expenses and key development and regulatory events and its decisions in the future.

Basis of Presentation

The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances among the consolidated entities have been eliminated from the consolidated financial statements.

The Company’s consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). Such consolidated financial statements reflect all adjustments that are, in management’s opinion, necessary to present fairly, in all material respects, the Company’s consolidated financial position, results of operations, and cash flows. There were no adjustments other than normal recurring adjustments.

Cash and Cash Equivalents

The Company generally considers cash equivalents to be all cash held in commercial checking accounts, certificates of deposit, money market accounts or investments in debt instruments with maturities of three months or less at the time of purchase. The carrying value of cash and cash equivalents approximates fair value due to the short-term nature of these items.

Restricted Cash

Restricted cash as of December 31, 2020 and 2019 reflects $796 and $134, respectively, in royalty revenue paid by Shionogi & Co., Ltd. (“Shionogi”) designated for interest on the PhaRMA Notes (defined in Note 3) and $1,425 and $1,417, respectively, the Company is required to maintain as collateral for a letter of credit associated with the lease execution and build-out of its new Birmingham research facilities.

Investments

The Company invests in high credit quality investments in accordance with its investment policy, which is designed to minimize the possibility of loss. The objective of the Company’s investment policy is to ensure the safety and preservation of invested funds, as well as maintaining liquidity sufficient to meet cash flow requirements. The Company places its excess cash with high credit quality financial institutions, commercial companies, and government agencies in order to limit the amount of its credit exposure. In accordance with its policy, the Company is able to invest in marketable debt securities that may consist of U.S. Government and government agency securities, money market and mutual fund investments, municipal and corporate notes and bonds, commercial paper and asset or mortgage-backed securities, among others. The Company’s investment policy requires it to purchase high-quality marketable securities with a maximum individual maturity of three years and requires an average portfolio maturity of no more than 18 months. Some of the securities the Company invests in may have market risk. This means that a change in prevailing interest rates may cause the principal amount of the investment to fluctuate. To minimize this risk, the Company schedules its investments with maturities that coincide with expected cash flow needs, thus avoiding the need to redeem an investment prior to its maturity date. Accordingly, the Company does not believe it has a material exposure to interest rate risk arising from its investments. Generally, the Company’s investments are not collateralized. The Company has not realized any significant losses from its investments.

The Company classifies all of its investments as available-for-sale. Unrealized gains and losses on investments are recognized in comprehensive loss, unless an unrealized loss is considered to be other than temporary, in which case the unrealized loss is charged to operations. The Company periodically reviews its investments for other than temporary declines in fair value below cost basis and whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company believes the individual unrealized losses represent temporary declines primarily resulting from interest rate changes. Realized gains and losses are reflected in interest and other income in the Consolidated Statements of Comprehensive Loss and are determined using the specific identification method with transactions recorded on a settlement date basis. Investments with original maturities at date of purchase beyond three months and which mature at or less than 12 months from the balance sheet date are classified as current. Investments with a maturity beyond 12 months from the balance sheet date are classified as long-term. At December 31, 2020, the Company believes that the cost of its investments is recoverable in all material respects.

The following tables summarize the fair value of the Company’s investments by type. The estimated fair values of the Company’s fixed income investments are classified as Level 2 in the fair value hierarchy as defined in U.S. GAAP. These valuations are based on observable direct and indirect inputs, primarily quoted prices of similar, but not identical, instruments in active markets or quoted prices for identical or similar instruments in markets that are not active. These fair values are obtained from independent pricing services which utilize Level 2 inputs.

	December 31, 2020
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	24,986	$	14	$	3	$	(3	)	$	25,000
Certificates of deposit		3,225		11		3		−			3,239
Total Investments	$	28,211	$	25	$	6	$	(3	)	$	28,239

	December 31, 2019
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	10,488	$	50	$	23	$	−		$	10,561
Corporate debt securities		9,742		59		10		(1	)		9,810
Certificates of deposit		1,669		7		7		−			1,683
Total Investments	$	21,899	$	116	$	40	$	(1	)	$	22,054

The Company’s investments at December 31, 2020 and 2019 have maturities of one year or less.

Receivables from Collaborations

Receivables from collaborations are recorded for amounts due to the Company related to reimbursable research and development costs from the U.S. Department of Health and Human Services, royalty receivables from Shionogi, Green Cross Corporation (“Green Cross”), Mundipharma International Holdings Limited (“Mundipharma”) and Seqirus UK Limited (“SUL”), and product sales to SUL. These receivables are evaluated to determine if any reserve or allowance should be established at each reporting date based on historical collection experience or specific circumstances and no amounts were recorded at December 31, 2020 and 2019.

At December 31, 2020 and December 31, 2019, the Company had the following receivables:

	December 31, 2020
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	−	$	5,402	$	5,402
Shionogi & Co. Ltd.		2,037		4		2,041
Green Cross Corporation		740		21		761
Mundipharma International Holdings Limited		39		−		39
Total receivables	$	2,816	$	5,427	$	8,243

	December 31, 2019
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	1,353	$	15,023	$	16,376
Shionogi & Co. Ltd.		1,336		4		1,340
Green Cross Corporation		2,924		8		2,932
Mundipharma International Holdings Limited		56		-		56
Seqirus UK Limited		1,091		351		1,442
Total receivables	$	6,760	$	15,386	$	22,146

Monthly invoices are submitted to the U.S. Department of Health and Human Services related to reimbursable research and development costs. The Company is also entitled to monthly reimbursement of indirect costs based on rates stipulated in the underlying contract. The Company’s calculations of its indirect cost rates are subject to audit by the U.S. Government.

Receivables from Product Sales

Receivables from product sales are recorded for amounts due to the Company related to sales of RAPIVAB and ORLADEYO. At December 31, 2020, receivables related to sales of RAPIVAB and ORLADEYO were $254 and $149, respectively. There were no receivables from product sales as of December 31, 2019. Receivables from product sales are evaluated to determine if any reserve or allowance should be recorded based on consideration of the current economic environment, expectations of future economic conditions and the Company’s own historical collection experience. No reserve or allowance amounts were recorded at December 31, 2020.

Inventory

At December 31, 2020 and 2019, the Company’s inventory related to peramivir which is being manufactured for the Company’s partners and the U.S. Government. Inventory as of December 31, 2020, consisted of raw materials of $206, work-in-process of $2,555 and finished goods of $4,548. As of December 31, 2019, the Company inventory consisted of peramivir finished goods of $276. Inventory is stated at the lower of cost and net realizable value, determined under the first-in, first-out (“FIFO”) method, or market. As of December 31, 2020 and 2019, the Company had inventory reserves of $270 and $276, respectively, for estimated unrecoverable capitalized inventory costs.

The Company expenses costs related to the production of inventories as research and development expenses in the period incurred until such time it is believed that future economic benefit is expected to be recognized, which generally is reliant upon receipt of regulatory approval. Upon regulatory approval, the Company capitalizes subsequent costs related to the production of inventories.

Property and Equipment

Property and equipment are recorded at cost. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Computer equipment is depreciated over a life of three years. Laboratory equipment, office equipment, and software are depreciated over a life of five years. Furniture and fixtures are depreciated over a life of seven years. Leasehold improvements are amortized over their estimated useful lives or the expected lease term, whichever is less.

In accordance with U.S. GAAP, the Company periodically reviews its property and equipment for impairment when events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Determination of recoverability is based on an estimate of undiscounted future cash flows resulting from the use of the asset and its eventual disposition. In the event that such cash flows are not expected to be sufficient to recover the carrying amount of the assets, the assets are written down to their estimated fair values. Property and equipment to be disposed of are reported at the lower of carrying amount or fair value less cost to sell.

Patents and Licenses

The Company seeks patent protection on all internally developed processes and products. All patent related costs are expensed to selling, general and administrative expenses when incurred as recoverability of such expenditures is uncertain.

Accrued Expenses

The Company generally enters into contractual agreements with third-party vendors who provide research and development, manufacturing, distribution, and other services in the ordinary course of business. Some of these contracts are subject to milestone-based invoicing and services are completed over an extended period of time. The Company records liabilities under these contractual commitments when it determines an obligation has been incurred, regardless of the timing of the invoice. This process involves reviewing open contracts and purchase orders, communicating with applicable Company personnel to identify services that have been performed on its behalf and estimating the level of service performed and the associated cost incurred for the service when the Company has not yet been invoiced or otherwise notified of actual cost. The majority of service providers invoice the Company monthly in arrears for services performed. The Company makes estimates of accrued expenses as of each balance sheet date in its financial statements based on the facts and circumstances. The Company periodically confirms the accuracy of its estimates with the service providers and makes adjustments if necessary. Examples of estimated accrued expenses include:

●

fees paid to Clinical Research Organizations (“CROs”) in connection with preclinical and toxicology studies and clinical trials;

	●	fees paid to investigative sites in connection with clinical trials;
	●	fees paid to contract manufacturers in connection with the production of the Company’s raw materials, drug substance, drug products, and product candidates; and

●

professional fees.

The Company bases its expenses related to clinical trials on its estimates of the services received and efforts expended pursuant to contracts with multiple research institutions and CROs that conduct and manage clinical trials on the Company’s behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. Payments under some of these contracts depend on factors such as the successful enrollment of patients and the completion of clinical trial milestones. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. As of December 31, 2020 and December 31, 2019, the carrying value of accrued expenses approximates their fair value due to their short-term settlement.

Accrued expenses were comprised of the following:

	December 31,
	2020		2019
Compensation and benefits	$	11,030	$	6,190
Development costs		15,150		11,302
Inventory		2,453		29
Professional fees		333		326
Duties and taxes		80		67
Other		4,896		3,451
Total accrued expenses	$	33,942	$	21,365

Income Taxes

The liability method is used in the Company’s accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse.

Accumulated Other Comprehensive Loss

Accumulated other comprehensive loss is comprised of unrealized gains and losses on available-for-sale investments and is disclosed as a separate component of stockholders’ equity. Amounts reclassified from accumulated other comprehensive loss are recorded as interest and other income on the Consolidated Statements of Comprehensive Loss. For the year ended December 31, 2020, realized gains of $1 were reclassified out of accumulated other comprehensive loss. No reclassifications out of accumulated other comprehensive loss were recorded in 2019.

Revenue Recognition

Collaborative and Other Research and Development Arrangements and Royalties

The Company recognizes revenue when it satisfies a performance obligation by transferring promised goods or services to a customer. Revenue is measured at the transaction price that is based on the amount of consideration that the Company expects to receive in exchange for transferring the promised goods or services to the customer. The transaction price includes estimates of variable consideration to the extent it is probable that a significant reversal of revenue recognized will not occur.

The Company has collaboration and license agreements with a number of third parties as well as research and development agreements with certain government entities. The Company’s primary sources of revenue are license, service, royalty and product sale revenues from these collaborative and other research and development arrangements.

Revenue from license fees, royalty payments, milestone payments, and research and development fees are recognized as revenue when the earnings process is complete and the Company has no further continuing performance obligations or the Company has completed the performance obligations under the terms of the agreement.

Arrangements that involve the delivery of more than one performance obligation are initially evaluated as to whether the intellectual property licenses granted by the Company represent distinct performance obligations. If they are determined to be distinct, the value of the intellectual property licenses would be recognized up-front while the research and development service fees would be recognized as the performance obligations are satisfied. For performance obligations based on services performed, the Company measures progress using an input method based on the effort we expend or costs we incur toward the satisfaction of performance obligation in relation to the total estimated effort of costs. Variable consideration is assessed at each reporting period as to whether it is not subject to significant future reversal and, therefore, should be included in the transaction price at the inception of the contract. If a contract includes a fixed or minimum amount of research and development support, this also would be included in the transaction price. Changes to collaborations, such as the extensions of the research term or increasing the number of targets or technology covered under an existing agreement, are assessed for whether they represent a modification or should be accounted for as a new contract. For contracts with multiple performance obligations, revenue is allocated to each performance obligation based on its relative standalone selling price. Standalone selling prices are based on observable prices at which the Company separately sells the products or services. If a standalone selling price is not directly observable, then the Company estimates the standalone selling price using either an adjusted market assessment approach or an expected cost plus margin approach, representing the amount that the Company believes the market is willing to pay for the product or service. Analyzing the arrangement to identify performance obligations requires the use of judgment, and each may be an obligation to deliver services, a right or license to use an asset, or another performance obligation.

Milestone payments are recognized as licensing revenue upon the achievement of specified milestones if (i) the milestone is substantive in nature and the achievement of the milestone was not probable at the inception of the agreement; and (ii) the Company has a right to payment. Any milestone payments received prior to satisfying these revenue recognition criteria are recorded as deferred revenue.

Reimbursements received for direct out-of-pocket expenses related to research and development costs are recorded as revenue in the Consolidated Statements of Comprehensive Loss rather than as a reduction in expenses. Under the Company’s contracts with the Biomedical Advanced Research and Development Authority within the United States Department of Health and Human Services (”BARDA/HHS”) and the National Institute of Allergy and Infectious Diseases (“NIAID/HHS”), revenue is recognized as reimbursable direct and indirect costs are incurred.

Under certain of the Company’s license agreements, the Company receives royalty payments based upon its licensees’ net sales of covered products. Royalties are recognized at the later of when (i) the subsequent sale or usage occurs, or (ii) the performance obligation to which some or all of the sales-based or usage-based royalty has been satisfied.

Product Sales

The Company’s principal sources of product sales are sales of peramivir to our licensing partners and sales of RAPIVAB to the U.S. Department of Health and Human Services under the Company’s procurement contract. In December 2020, the Company launched ORLADEYO and began recording product revenue. The Company recognizes revenue for sales when the customer obtains control of the product, which generally occurs upon delivery.

The Company recorded the following revenues for the years ended December 31:

	2020		2019		2018
Product sales, net	$	3,301	$	17,533	$	−
Royalty revenue		3,381		6,303		6,101
Collaborative and other research and development revenues:
U.S. Department of Health and Human Services		9,231		4,898		2,552
Torii Pharmaceutical Co., Ltd.		1,899		20,101		−
Seqirus UK Limited		−		−		12,000
Total collaborative and other research and development revenues		11,130		24,999		14,552
Total revenues	$	17,812	$	48,835	$	20,653

Advertising

The Company engages in very limited distribution and direct-response advertising when promoting RAPIVAB. Advertising and promotional costs are expensed in “Selling, general and administrative” as the costs are incurred. Advertising expenses related to the launch of ORLADEYO were $6,567 for year ended December 31, 2020. The Company did not incur advertising and product promotion expenses in 2019 and 2018.

Research and Development Expenses

The Company’s research and development costs are charged to expense when incurred. Research and development expenses include all direct and indirect development costs related to the development of the Company’s portfolio of product candidates. Advance payments for goods or services that will be used or rendered for future research and development activities are deferred and capitalized. Such amounts are recognized as expense when the related goods are delivered or the related services are performed. Research and development expenses include, among other items, personnel costs, including salaries and benefits, manufacturing costs, clinical, regulatory, and toxicology services performed by CROs, materials and supplies, and overhead allocations consisting of various administrative and facilities related costs. Most of the Company’s manufacturing and clinical and preclinical studies are performed by third-party CROs. Costs for studies performed by CROs are accrued by the Company over the service periods specified in the contracts and estimates are adjusted, if required, based upon the Company’s on-going review of the level of services actually performed.

Additionally, the Company has license agreements with third parties, such as Albert Einstein College of Medicine of Yeshiva University (“AECOM”), Industrial Research, Ltd. (“IRL”), and the University of Alabama at Birmingham (“UAB”), which require fees related to sublicense agreements or maintenance fees. The Company expenses sublicense payments as incurred unless they are related to revenues that have been deferred, in which case the expenses are deferred and recognized over the related revenue recognition period. The Company expenses maintenance payments as incurred.

Deferred collaboration expenses represent sub-license payments, paid to the Company’s academic partners upon receipt of consideration from various commercial partners, and other consideration paid to the Company’s academic partners for modification to existing license agreements. These deferred expenses would not have been incurred without receipt of such payments or modifications from the Company’s commercial partners and are being expensed in proportion to the related revenue being recognized. The Company believes that this accounting treatment appropriately matches expenses with the associated revenue.

Stock-Based Compensation

All share-based payments, including grants of stock option awards and restricted stock unit awards, are recognized in the Company’s Consolidated Statements of Comprehensive Loss based on their fair values. The fair value of stock option awards is estimated using the Black-Scholes option pricing model. The fair value of restricted stock unit awards is based on the grant date closing price of the common stock. Stock-based compensation cost is recognized as expense on a straight-line basis over the requisite service period of the award. In addition, we have outstanding performance-based stock options for which no compensation expense is recognized until “performance” is deemed to have occurred.

Interest Expense and Royalty Financing Obligation

The royalty financing obligation is eligible to be repaid based on royalties from net sales of ORLADEYO. Interest expense is accrued using the effective interest rate method over the estimated period the related liability will be paid. This requires the Company to estimate the total amount of future royalty payments to be generated from product sales over the life of the agreement. The Company imputes interest on the carrying value of the royalty financing obligation and records interest expense using an imputed effective interest rate. The Company will reassess the expected royalty payments each reporting period and account for any changes through an adjustment to the effective interest rate on a prospective basis. The assumptions used in determining the expected repayment term of the debt and amortization period of the issuance costs requires that the Company make estimates that could impact the carrying value of the liability, as well as the period over which associated issuance costs will be amortized. A significant increase or decrease in forecasted net sales could materially impact the liability balance, interest expense and the time period for repayment.

Interest Expense and Deferred Financing Costs

Interest expense for the years ended December 31, 2020, 2019 and 2018 was $14,501 $11,892 and $9,176, respectively, and primarily relates to the issuance of the PhaRMA Notes (defined in Note 3) and the Prior Credit Facility and Amended and Restated Senior Credit Facility (each defined in Note 4). Costs directly associated with the issuance of the PhaRMA Notes, the Prior Credit Facility and the Amended and Restated Senior Credit Facility have been capitalized and are netted against the non-recourse notes payable and senior credit facility on the Consolidated Balance Sheets. These costs are being amortized to interest expense over the terms of the PhaRMA Notes and the Amended and Restated Senior Credit Facility (as subsequently amended and restated) using the effective interest rate method. In December 2020, the Company incurred costs directly associated with its royalty monetization (defined in Note 3) and borrowings under the Credit Agreement (defined in Note 4). These costs have been deferred and are being amortized to interest expense over the terms of the respective arrangements. Amortization of deferred financing costs and original issue discount included in interest expense was $1,217, $1,278 and $885 for each of the years ended December 31, 2020, 2019 and 2018, respectively. In December 2020, the outstanding principal balance of the Senior Credit Facility was repaid and related unamortized deferred financing costs and original issue discount of $1,211 were fully expensed as part of loss on debt extinguishment.

Currency Hedge Agreement

In connection with the issuance by Royalty Sub of the PhaRMA Notes, the Company entered into a Currency Hedge Agreement to hedge certain risks associated with changes in the value of the Japanese yen relative to the U.S. dollar. The final tranche of the options under the Currency Hedge Agreement expired in November of 2020. The Currency Hedge Agreement did not qualify for hedge accounting treatment; therefore mark-to-market adjustments were recognized in the Company’s Consolidated Statements of Comprehensive Loss. Cumulative mark-to-market adjustments for the years ended December 31, 2020, 2019 and 2018 resulted in losses of $632, $347 and $1,049, respectively. Mark-to-market adjustments were determined by a third-party pricing model which uses quoted prices in markets that are not actively traded and for which significant inputs are observable directly or indirectly, representing Level 2 in the fair value hierarchy as defined by U.S. GAAP. In addition, realized currency exchange gains of $662, $863 and $941 were recognized in 2020, 2019 and 2018, respectively, related to the exercise of a U.S. dollar/Japanese yen currency option under the Company’s foreign currency hedge.

Net Loss Per Share

Net loss per share is based upon the weighted average number of common shares outstanding during the period. Diluted loss per share is equivalent to basic net loss per share for all periods presented herein because common equivalent shares from unexercised stock options, outstanding warrants, and common shares expected to be issued under the Company’s employee stock purchase plan were anti-dilutive. The calculation of diluted earnings per share for the years ended December 31, 2020, 2019, and 2018 does not include 14,957, 2,805, and 2,274, respectively, of potential common shares as their impact would be anti-dilutive.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. The most significant estimates in the Company’s consolidated financial statements relate to the valuation of stock options, the royalty financing and the valuation allowance for deferred tax assets resulting from net operating losses. These estimates are based on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates.

Significant Customers and Other Risks

Significant Customers

Other than royalty revenues, the Company’s primary sources of revenue that have an underlying cash flow stream are the reimbursement of galidesivir (formerly BCX4430) development expenses earned under cost-plus-fixed-fee contracts with BARDA/HHS and NIAID/HHS and sales of RAPIVAB (peramivir injection) under our procurement contract with the Assistant Secretary for Preparedness and Response within the United States Department of Health and Human Services. The Company relies on BARDA/HHS and NIAID/HHS to reimburse predominantly all of the development costs for its galidesivir program. Accordingly, reimbursement of these expenses represents a significant portion of the Company’s collaborative and other research and development revenues. The completion or termination of the NIAID/HHS and BARDA/HHS galidesivir contracts could negatively impact the Company’s future Consolidated Statements of Comprehensive Loss and Cash Flows. The Company recognizes royalty revenue from the net sales of RAPIACTA by Shionogi; however, the underlying cash flow from these royalty payments, except for Japanese government stockpiling sales, goes directly to pay the interest, and then the principal, on the Company’s non-recourse notes payable. Payment of the interest and the ultimate repayment of principal of these notes will be entirely funded by future royalty payments derived from net sales of RAPIACTA. Further, the Company’s drug development activities are performed by a limited group of third-party vendors. If any of these vendors were unable to perform their services, this could significantly impact the Company’s ability to complete its drug development activities.

Risks from Third Party Manufacturing and Distribution Concentration

The Company relies on single source manufacturers for active pharmaceutical ingredient and finished drug product manufacturing of product candidates in development and on single source distributors for distribution of approved drug products. Delays in the manufacture or distribution of any product could adversely impact the commercial revenue and future procurement stockpiling of the Company’s product candidates in development.

Credit Risk

Cash equivalents and investments are financial instruments which potentially subject the Company to concentration of risk to the extent recorded on the Consolidated Balance Sheets. The Company deposits excess cash with major financial institutions in the United States. Balances may exceed the amount of insurance provided on such deposits. The Company believes it has established guidelines for investment of its excess cash relative to diversification and maturities that maintain safety and liquidity. To minimize the exposure due to adverse shifts in interest rates, the Company maintains a portfolio of investments with an average maturity of approximately 18 months or less. Other than product sale and collaborative partner receivables discussed above, the majority of the Company’s receivables from collaborations are due from the U.S. Government, for which there is no assumed credit risk.

Recent Accounting Pronouncements

In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. In addition, ASU 2016-13 requires credit losses relating to available-for-sale debt securities to be recorded through an allowance for credit losses. ASU 2016-13 requires consideration of a broader range of reasonable and supportable information to develop credit loss estimates. ASU 2016-13 is effective for public companies for interim and annual periods beginning after December 15, 2019. The Company adopted ASU 2016-02 as of January 1, 2020. Given the nature of the Company’s receivables from collaborators, investment portfolio and other financial assets, adoption of this standard did not have a material effect on the Company's financial position, results of operations or cash flows.

In August 2018, the FASB issued Accounting Standards Update No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) (“ASU 2018-15”). ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The guidance requires entities to capitalize costs for certain implementation activities in the application development stage and expense the capitalized implementation costs over the expected term of the hosting arrangement. ASU 2018-15 is effective for fiscal years beginning after December 15, 2019, with early adoption permitted. The Company elected to adopt this standard early, beginning October 1, 2019 on a prospective basis. Adoption did not have a material effect on the Company's financial position, results of operations or cash flows.

The Company has reviewed other new accounting pronouncements that were issued as of December 31, 2020 and does not believe that these pronouncements are either applicable to the Company, or that they will have a material impact on its financial position or results of operations.

Note 2 - Property and Equipment

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment Disclosure [Text Block]

Note 2 — Property and Equipment

Property and equipment consisted of the following at December 31:

	2020			2019
Furniture and fixtures	$	722		$	602
Office equipment		211			184
Software		1,159			1,159
Laboratory equipment		3,774			3,462
Leasehold improvements		8,583			8,528
		14,449			13,935
Less accumulated depreciation and amortization		(7,336	)		(6,588	)
Property and equipment, net	$	7,113		$	7,347

Depreciation and amortization expense for the years ended December 31, 2020, 2019, and 2018 was $748, $724, and $770, respectively.

Note 3 - Royalty Monetizations

12 Months Ended

Dec. 31, 2020

Royalty Monetization [Text Block]

Note 3—Royalty Monetizations

RAPIACTA Royalty Monetizations

Overview

On March 9, 2011, the Company completed a $30,000 financing transaction to monetize certain future royalty and milestone payments under the Company’s agreement with Shionogi (the “Shionogi Agreement”), pursuant to which Shionogi licensed from the Company the rights to market RAPIACTA in Japan and Taiwan. The Company received net proceeds of $22,691 from the transaction after transaction costs of $4,309 and the establishment of a $3,000 interest reserve account by Royalty Sub, available to help cover interest shortfalls in the future. All of the interest reserve account has been fully utilized with the September 2012 interest payment.

As part of the transaction, the Company entered into a purchase and sale agreement dated as of March 9, 2011 with JPR Royalty Sub, LLC, a wholly-owned subsidiary of the Company (“Royalty Sub”), whereby the Company transferred to Royalty Sub, among other things, (i) its rights to receive certain royalty and milestone payments from Shionogi arising under the Shionogi Agreement, and (ii) the right to receive payments under a Japanese yen/US dollar foreign currency hedge arrangement (as further described below, the “Currency Hedge Agreement”) put into place by the Company in connection with the transaction. Royalty payments are paid by Shionogi in Japanese yen, and any milestone payments will be paid in U.S. dollars. The Company’s collaboration with Shionogi was not impacted as a result of this transaction.

Non-Recourse Notes Payable

On March 9, 2011, Royalty Sub completed a private placement to institutional investors of $30,000 in aggregate principal amount of its PhaRMA Senior Secured 14.0% Notes due on December 1, 2020 (the “PhaRMA Notes”). The PhaRMA Notes were issued by Royalty Sub under an Indenture, dated as of March 9, 2011 (the “Indenture”), by and between Royalty Sub and U.S. Bank National Association, as Trustee. Principal and interest on the PhaRMA Notes issued are payable from, and are secured by, the rights to royalty and milestone payments under the Shionogi Agreement transferred by the Company to Royalty Sub and payments, if any, made to Royalty Sub under the Currency Hedge Agreement. The PhaRMA Notes bear interest at 14% per annum, payable annually in arrears on September 1st of each year. The Company remains entitled to receive any royalties and milestone payments related to sales of peramivir by Shionogi following repayment of the PhaRMA Notes.

Royalty Sub’s obligations to pay principal and interest on the PhaRMA Notes are obligations solely of Royalty Sub and are without recourse to any other person, including the Company, except to the extent of the Company’s pledge of its equity interests in Royalty Sub in support of the PhaRMA Notes. The Company may, but is not obligated to, make capital contributions to a capital account that may be used to redeem, or on up to one occasion pay any interest shortfall on, the PhaRMA Notes.

In September 2014, Royalty Sub was unable to pay the accrued interest obligation due September 3, 2013. Under the terms of the Indenture, Royalty Sub’s inability to pay the full amount of interest payable in September 2013 by the next succeeding payment date for the PhaRMA Notes, which was September 1, 2014, constituted an event of default. Accordingly, the PhaRMA Notes and related accrued interest have been classified as current liabilities on the December 31, 2014 balance sheet, and thereafter. As a result of the event of default under the PhaRMA Notes, the holders of the PhaRMA Notes may foreclose on the collateral securing the PhaRMA Notes and the equity interest in Royalty Sub and exercise other remedies available to them under the Indenture in respect of the PhaRMA Notes. In such event, the Company may not realize the benefit of future royalty payments that might otherwise accrue to it following repayment of the PhaRMA Notes and it might otherwise be adversely affected. Due to the non-recourse nature of the PhaRMA Notes, in the event of any potential foreclosure, the primary impact to the Company would be the loss of future royalty payments from Shionogi and legal costs associated with retiring the PhaRMA Notes. As the PhaRMA Notes are the obligation of Royalty Sub and non-recourse to the Company, the event of default of the PhaRMA Notes is not expected to have a significant impact on the Company’s future results of operations or cash flows. The PhaRMA Notes had a final legal maturity date of December 1, 2020, at which time the outstanding principal amount of the PhaRMA Notes of $30,000, together with accrued and unpaid interest of $20,614, was due in full. As of December 31, 2020, the PhaRMA Notes remain outstanding and in default and the Company will continue to record the liability and accrued interest owed until the Company is determined to no longer be the financial obligor.

The Indenture does not contain any financial covenants. The Indenture includes customary representations and warranties of Royalty Sub, affirmative and negative covenants of Royalty Sub, Events of Default and related remedies, and provisions regarding the duties of the Trustee, indemnification of the Trustee, and other matters typical for indentures used in structured financings of this type.

As of December 31, 2020, the aggregate fair value of the PhaRMA Notes was estimated to be approximately 3% of its carrying value of $30,000. The estimated fair value of the PhaRMA Notes is classified as Level 3 in the fair value hierarchy as defined in U.S. GAAP.

Foreign Currency Hedge

In connection with the issuance by Royalty Sub of the PhaRMA Notes, the Company entered into a Currency Hedge Agreement to hedge certain risks associated with changes in the value of the Japanese yen relative to the U.S. dollar. Under the Currency Hedge Agreement, the Company had the right to purchase dollars and sell yen at a rate of 100 yen per dollar. The final tranche of the options under the Currency Hedge Agreement expired in November of 2020.

The Currency Hedge Agreement did not qualify for hedge accounting treatment; therefore mark-to-market adjustments were recognized in the Company’s Consolidated Statements of Comprehensive Loss. Cumulative mark-to-market adjustments in 2020, 2019 and 2018 resulted in losses of $632, $347 and $1,049, respectively. In addition, realized currency exchange gains of $662, $863 and $941 were recognized in 2020, 2019 and 2018, respectively, related to the exercise of a U.S. dollar/Japanese yen currency option under the Company’s foreign currency hedge.

ORLADEYO Royalty Monetization

On December 7, 2020, the Company and RPI 2019 Intermediate Finance Trust (“RPI”) entered into a Purchase and Sale Agreement (the “Royalty Purchase Agreement”), pursuant to which the Company sold to RPI the right to receive certain royalty payments from the Company for a purchase price of $125,000 in cash (the “Royalty Sale”). Under the Royalty Purchase Agreement, RPI is entitled to receive tiered, sales-based royalties on net product sales of ORLADEYO in the United States, certain key European markets, and other markets where the Company sells ORLADEYO directly or through distributors (collectively, the “Key Territories”) in an amount equal to: (i) 8.75% of aggregate annual net sales of ORLADEYO in the Key Territories for annual net sales up to $350,000 and (ii) 2.75% of annual net sales in the Key Territories for annual net sales between $350,000 and $550,000. No royalty payments are payable on annual net sales in the Key Territories over $550,000. In addition, RPI will be entitled to receive 1.0% of global net sales, if any, of BCX9930.

Under the Royalty Purchase Agreement, RPI is also entitled to receive a tiered revenue share on ORLADEYO sublicense revenue or net sales by licensees outside of the Key Territories (the “Other Markets”) equal to: (i) 20% of the proceeds received by the Company for upfront license fees and development milestones for ORLADEYO in the Other Markets; (ii) 20% of proceeds received on annual net sales of up to $150,000 in the Other Markets; and (iii) 10% of proceeds received by the Company on annual net sales between $150,000 and $230,000 in the Other Markets. No royalty payments are payable on annual net sales above $230,000 in the Other Markets. No payment will be due to RPI for any achievement milestone which may be payable under the existing out-license for ORLADEYO.

The Company will be required to make royalty payments of amounts owed to RPI each calendar quarter following the first commercial sale of ORLADEYO in any country.

Under the Royalty Purchase Agreement, the Company has agreed to specified affirmative and negative covenants, including covenants regarding periodic reporting of information by the Company to RPI, third-party audits of royalties paid under the Royalty Purchase Agreement, and restrictions on the ability of the Company or any of its subsidiaries to incur indebtedness other than certain royalty sales and as is permitted to be incurred under the terms of the Company’s Credit Agreement with Athyrium Opportunities III Co-Invest 1 LP. Refer to Note 4 for further details on the Credit Agreement. The restrictions on the ability of the Company or any of its subsidiaries to incur indebtedness are eliminated after the achievement of certain specified milestones in the Royalty Purchase Agreement.

The cash consideration of $125,000 obtained pursuant to the Royalty Purchase Agreement is recorded in “Royalty financing obligation” on the Company’s consolidated balance sheet as of December 31, 2020. The fair value for the royalty financing obligation at the time of the transaction was based on the Company’s estimates of future royalties expected to be paid to RPI over the life of the arrangement. The estimates of future net product sales (and resulting royalty payments) are based on key assumptions including population, penetration and sales price and are determined using forecasts from market data sources, which are considered Level 3 inputs. Deferred issuance costs, which consist primarily of advisory and legal fees, totaled $2,370 as of December 31, 2020. The liability and the deferred issuance costs are amortized using the effective interest method over the term of the arrangement, in accordance with the respective guidance. The effective interest rate as of December 31, 2020 was approximately 24%. For 2020, accrued interest expense in the amount of $2,108 was added to the initial balance of the liability. The Company will utilize the prospective method to account for subsequent changes in the estimated future payments to be made to RPI.

Note 4 - Credit Agreement	12 Months Ended
Note 4 - Credit Agreement	Dec. 31, 2020
Senior Credit Facility [Member]
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 5 — Senior Credit Facility On February 5, 2019, the Company entered into a $100,000 Senior Credit Facility with an affiliate of MidCap Financial Services, LLC, as administrative agent (the “Second Amended and Restated Senior Credit Facility”). Borrowings under the Second Amended and Restated Senior Credit Facility were available in three tranches, with (i) the first tranche comprised of $50,000 funded at closing, which included $30,000 of proceeds that were deemed rolled over from the outstanding principal amount under the Company’s prior credit agreement, (ii) the second tranche comprised of $30,000, and (iii) the third tranche comprised of $20,000, with the second and third tranches to have been funded upon the completion of certain contingencies related to the Company’s development activities of its product candidates and the establishment of certain financial covenants. On September 10, 2019 the Company executed the first amendment to the Second Amended and Restated Credit Facility which extended the commitment termination date for the second tranche to November 30, 2019. On November 30, 2019, the Company’s access to the second tranche expired. The Second Amended and Restated Senior Credit Facility refinanced and replaced the Amended and Restated Senior Credit Facility dated as of July 20, 2018 (the “Amended and Restated Senior Credit Facility”). The Second Amended and Restated Senior Credit Facility had a variable interest rate of LIBOR (which was not to be less than 0.5%) plus 8%. The Second Amended and Restated Senior Credit Facility included an interest-only payment period through June 2020 and scheduled monthly principal and interest payments for the subsequent 30 months. The Company used a portion of the proceeds of the Second Amended and Restated Senior Credit Facility to pay off outstanding amounts under the Amended and Restated Senior Credit Facility and the remainder was used for general corporate purposes. In December 2020, the Company repaid the outstanding principal of the Second Amended and Restated Senior Credit Facility of $40,000 along with exit fees and accrued interest through the payoff date that totaled $3,298. The unamortized deferred financing cost and original issue discount of $1,211 was expensed as a loss on debt extinguishment.
Credit Agreement [Member]
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 4 — Credit Agreement On December 7, 2020, the Company entered into a $200,000 Credit Agreement with Athyrium Opportunities III Co-Invest 1 LP (“Athyrium”), as lender and as administrative agent for the lenders. BioCryst Ireland Limited, BioCryst US Sales Co., LLC, and BioCryst UK Limited, each of which is a wholly-owned subsidiary of the Company, are guarantors to the Credit Agreement. The Credit Agreement provides for an initial term loan in the principal amount of $125,000 (the “Term A Loan”), which was received by the Company on December 7, 2020 and is recorded in “Secured term loan” on the Company’s balance sheet as of December 31, 2020. The Company used a portion of the proceeds from the Term A Loan to repay $43,298 of outstanding indebtedness, including accrued interest, under its existing credit facility with MidCap Financial Trust. The Company intends to use the remaining proceeds to support the launch of ORLADEYO in the United States and Europe and to advance the development of BCX9930 into clinical trials in multiple complement-mediated diseases, and for other general corporate purposes. The Credit Agreement also provides for two additional term loans, at the Company's option, in the respective principal amounts of $25,000 (the “Term B Loan”) and $50,000 (the “Term C Loan”). The Term B Loan and the Term C Loan may be drawn upon if, among other conditions, the Company reaches defined revenue milestones and, with respect to a draw on the Term C Loan, the Term B Loan has been funded prior to or contemporaneously with the Term C Loan. The maturity date of the Credit Agreement is December 7, 2025. The Credit Agreement provides for quarterly interest-only payments until the maturity date, with the unpaid principal amount of the outstanding Term Loans due and payable on the maturity date. For each of the first eight full fiscal quarters following December 7, 2020, the Company has the option to make the applicable interest payment-in-kind (a “PIK Interest Payment”) by capitalizing the entire amount of interest accrued during the applicable interest period with the unpaid original principal amount outstanding on the last day of such period. The Term Loans will bear interest at a rate equal to the three-month LIBOR rate, which shall be no less than 1.75% and no more than 3.50% (“LIBOR”), plus 8.25%, or for each interest period in which a PIK Interest Payment is made, the LIBOR plus 10.25%. Subject to certain exceptions, the Company is required to make mandatory prepayments of the Term Loans with the proceeds of certain asset sales, certain ORLADEYO out-licensing or royalty monetization transactions (excluding the Royalty Sale), extraordinary receipts, debt issuances, or upon a change of control of the Company and specified other events, subject to certain exceptions. The Company may make voluntary prepayments in whole or in part. Prepayments are subject to a premium equal to, (i) with respect to any voluntary prepayment and certain mandatory prepayments paid on or prior to the second anniversary of the applicable Term Loan borrowing date, the amount, if any, by which (a) the sum of (1) 102.00% of the principal amount of the Term Loan being prepaid plus (2) the present value of all interest that would have accrued on the principal amount of the Term Loan being prepaid through and including the second anniversary of the date of the borrowing of such Term Loan, plus 0.50%, exceeds (b) the principal amount of the Term Loan being prepaid; (ii) with respect to any prepayment made between the second and third anniversaries of the applicable Term Loan borrowing date, 2.00% of the principal amount of the Term Loan being prepaid; (iii) with respect to any prepayment made between the third and fourth anniversaries of the applicable Term Loan borrowing date, 1.00% of the principal amount of the Term Loan being prepaid; and (iv) with respect to any prepayment made after the fourth anniversary of the applicable Term Loan borrowing date, 0.00% of the principal amount of the Term Loan being prepaid. Upon the prepayment or repayment, including at maturity, of all or any of the Term Loans, the Company is obligated to pay an exit fee in an amount equal to 2.00% of the principal amount of the Term Loans prepaid or repaid. In addition, each Term Loan is subject to a 1.00% commitment fee at its respective borrowing date. The Credit Agreement also contains representations and warranties and affirmative and negative covenants customary for financings of this type, as well as customary events of default. Certain of the customary negative covenants limit the ability of the Company and certain of its subsidiaries to, among other things, grant liens, make investments, incur additional indebtedness, engage in mergers, acquisitions, and similar transactions, dispose of assets, license certain property, distribute dividends, make certain restricted payments, change the nature of the Company's business, engage in transactions with affiliates and insiders, prepay other indebtedness, or engage in sale and leaseback transactions, subject to certain exceptions. Additionally, as of the last day of each fiscal quarter (a “Test Date”), beginning with the first Test Date occurring immediately after the Term C Loan is drawn, if applicable, the Company may not permit consolidated net revenues from ORLADEYO sales in the United States for the four-fiscal quarter period ending on such Test Date to be less than the specified amounts set forth in the Credit Agreement (collectively, the “Revenue Tests”). If the Company fails to satisfy the Revenue Tests as of any Test Date, it will have a one-time right (the “Cure Right”) to repay in full the entire amount of the Term C Loans outstanding at such time together with all accrued and unpaid interest thereon plus the prepayment premium, exit fee, and any other fees or amounts payable under the Credit Agreement at such time. In addition, the Credit Agreement contains a minimum liquidity covenant requiring the Company to maintain at all times, as applicable, at least $15,000 of unrestricted cash and cash equivalents if only the Term A Loan has been drawn; at least $20,000 of unrestricted cash and cash equivalents if the Term B Loan has been drawn but the Term C Loan has not been drawn; and at least $15,000 (or, if the Cure Right has been exercised, $20,000) of unrestricted cash and cash equivalents if the Term C Loan has been drawn, subject to certain exceptions. A failure to comply with the covenants in the Credit Agreement could permit the Lenders under the Credit Agreement to declare the outstanding principal as well as accrued interest and fees, to be immediately due and payable. The Company's obligations under the Credit Agreement are secured by a security interest in, subject to certain exceptions, substantially all of the Company's assets. As of December 31, 2020, the Company had borrowings of $125,000 under the Credit Agreement. The carrying amount of the debt approximates its fair value based on prevailing interest rates as of the balance sheet date. The Credit Agreement provides for quarterly interest-only payments until the maturity date, with the unpaid principal amount of the outstanding Term Loans due and payable on the maturity date of December 7, 2025. The Company has elected the first quarterly interest payment to be a PIK Interest Payment and began accruing interest at a rate of 12.17%. As of December 31, 2020, debt fees and issuance costs totaled $7,764 and are being amortized as interest expense on an effective interest rate method over the term of the Term A Loan. Interest expense of $925, net of deferred financing amortization of $131, related to the Credit Agreement was recognized in 2020 related to the Term A Loan. The Credit Agreement contains two provisions that, if deemed probable, would create the recognition of an embedded feature; however, at this time, the Company does not believe either provision is probable.

Note 5 - Senior Credit Facility	12 Months Ended
Note 5 - Senior Credit Facility	Dec. 31, 2020
Senior Credit Facility [Member]
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 5 — Senior Credit Facility On February 5, 2019, the Company entered into a $100,000 Senior Credit Facility with an affiliate of MidCap Financial Services, LLC, as administrative agent (the “Second Amended and Restated Senior Credit Facility”). Borrowings under the Second Amended and Restated Senior Credit Facility were available in three tranches, with (i) the first tranche comprised of $50,000 funded at closing, which included $30,000 of proceeds that were deemed rolled over from the outstanding principal amount under the Company’s prior credit agreement, (ii) the second tranche comprised of $30,000, and (iii) the third tranche comprised of $20,000, with the second and third tranches to have been funded upon the completion of certain contingencies related to the Company’s development activities of its product candidates and the establishment of certain financial covenants. On September 10, 2019 the Company executed the first amendment to the Second Amended and Restated Credit Facility which extended the commitment termination date for the second tranche to November 30, 2019. On November 30, 2019, the Company’s access to the second tranche expired. The Second Amended and Restated Senior Credit Facility refinanced and replaced the Amended and Restated Senior Credit Facility dated as of July 20, 2018 (the “Amended and Restated Senior Credit Facility”). The Second Amended and Restated Senior Credit Facility had a variable interest rate of LIBOR (which was not to be less than 0.5%) plus 8%. The Second Amended and Restated Senior Credit Facility included an interest-only payment period through June 2020 and scheduled monthly principal and interest payments for the subsequent 30 months. The Company used a portion of the proceeds of the Second Amended and Restated Senior Credit Facility to pay off outstanding amounts under the Amended and Restated Senior Credit Facility and the remainder was used for general corporate purposes. In December 2020, the Company repaid the outstanding principal of the Second Amended and Restated Senior Credit Facility of $40,000 along with exit fees and accrued interest through the payoff date that totaled $3,298. The unamortized deferred financing cost and original issue discount of $1,211 was expensed as a loss on debt extinguishment.

Note 6 - Lease Obligations and Other Contingencies

12 Months Ended

Dec. 31, 2020

Leases of Lessor Disclosure [Text Block]

Note 6 — Lease Obligations and Other Contingencies

In February 2016, the FASB issued ASU 2016-02: Leases (Topic 842). This ASU requires a lessee to recognize a right-of-use asset and a lease liability on its balance sheet for most operating leases. ASU 2016-02 is effective for annual and interim periods beginning after December 15, 2018, including interim periods within those fiscal years. In July 2018, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements, which provides companies with an additional optional transition method to apply the new standard to leases in effect at the adoption date through a cumulative effect adjustment. The Company adopted the new lease standard as of January 1, 2019 using this optional transition method.

The Company elected the package of practical expedients referenced in ASU 2016-02, which permits companies to retain original lease identification and classification without reassessing initial direct costs for existing leases. The Company also elected the practical expedient that exempts leases with an initial lease term of twelve months or less, as well as the practical expedient that allows companies to select, by class of underlying asset, not to separate lease and non-lease components. Adoption of this standard resulted in the recognition of a right-of-use asset and a lease liability on the Company’s January 1, 2019 Consolidated Balance Sheet of $3,621 and $4,822, respectively. There was no material impact on the Company’s Consolidated Statement of Comprehensive Loss, and the cumulative transition adjustment recorded to retained earnings upon adoption was $238.

The Company leases certain assets under operating leases, which primarily consisted of real estate leases, laboratory equipment leases and office equipment leases as of December 31, 2020. Certain operating leases provide for renewal options, which can vary by lease. The right-of-use asset and lease liabilities on the Company’s Consolidated Balance Sheet represent payments over the lease term, which includes renewal options for certain real estate leases that we are likely to exercise. As part of the Company’s assessment of the lease term, the Company elected the hindsight practical expedient, which allows companies to use current knowledge and expectations when determining the likelihood to extend lease options. Renewal options for our leases range from 1 to 5 years in length and begin from 2023 through 2026. The weighted average lease term for the Company’s operating leases was 13.1 years. The discount rate used in the calculation of the Company’s right-of-use asset and lease liability was determined based on the stated rate within each contract when available, or the Company’s collateralized borrowing rate from lending institutions. The weighted average discount rate for the Company’s operating leases was 12.7%.

The Company has not made any residual value guarantees related to its operating leases; therefore, the Company has no corresponding liability recorded on its Consolidated Balance Sheets.

Aggregate lease expense under operating leases was $1,754 and $1,464 for the twelve-month periods ended December 31, 2020 and 2019, respectively. Certain operating leases include rent escalation provisions, which the Company recognizes as expense on a straight-line basis. Lease expense for leases with an initial term of twelve months or less was not material.

Future lease payments for assets under operating leases as of December 31, 2020, are as follows:

Remaining Maturities of Lease Liabilities
Year Ending December 31,	Operating Leases
2021	$	1,302
2022		758
2023		619
2024		577
2025		582
Thereafter		7,327
Total lease payments		11,165
Less imputed interest		6,115
Total	$	5,050

The Company’s current lease liability at December 31, 2020 and 2019 was $1,179 and $1,377, respectively. The Company’s long-term lease liability as of December 31, 2020 and 2019 was $3,871 and $3,406, respectively. The current and long-term portions of the Company’s lease liability are presented within “Lease financing obligations” on the Consolidated Balance Sheets. Cash paid for amounts included in the measurement of lease liabilities was $1,696 and $1,457 for the years ended December 31, 2020 and 2019, respectively. The Company’s right-of use asset balance associated with operating leases totaled $3,802 and $3,590 at December 31, 2020 and 2019, respectively. These amounts are presented within “Other assets” on the Consolidated Balance Sheets. Operating right-of-use assets are recorded net of accumulated amortization of $2,641 and $1,386 as of December 31, 2020 and 2019, respectively.

Note 7 - Stockholders' Equity

12 Months Ended

Dec. 31, 2020

Stockholders' Equity Note Disclosure [Text Block]

Note 7 — Stockholders’ Equity

Sales of Common Stock

On November 8, 2017, the Company filed a $200,000 shelf registration statement on Form S-3 with the SEC. This shelf registration statement became effective on December 12, 2017 and allowed the Company to sell securities, including common stock, preferred stock, depository shares, stock purchase contracts, warrants and units, from time to time at prices and on terms to be determined at the time of sale.

On August 6, 2018, the Company completed an underwritten public offering of 10,455 shares of its common stock, offered at a price to the public of $5.50 per share, including shares issued pursuant to the underwriters’ 30-day option to purchase additional shares, which was exercised in full. The net proceeds from this offering were approximately $53,400 after deducting underwriting discounts and commissions and estimated offering expenses.

On November 18, 2019, the Company completed an underwritten public offering of 43,621 shares of its common stock, offered at a price to the public of $1.45 per share, including shares issued pursuant to the underwriters’ 30-day option to purchase additional shares, which was exercised in full. The net proceeds from this offering were approximately $58,500 after deducting underwriting discounts and commissions and estimated offering expenses.

On November 21, 2019, the Company completed an offering of pre-funded warrants to purchase up to 11,765 shares of its common stock at a price of $1.69 per warrant. Each pre-funded warrant is exercisable subject to conditions in the warrant agreement into 1 share of common stock at an exercise price of $0.01 per share. The net proceeds from this offering were $19,882, excluding any proceeds the Company may receive upon the subsequent exercise of the pre-funded warrants. All warrants issued in this offering remain outstanding at December 31, 2020.

On April 24, 2020, the Company filed a $500,000 shelf registration statement on Form S-3 with the SEC. This shelf registration statement became effective on May 14, 2020 and allows the Company to sell securities, including common stock, preferred stock, depository shares, purchase contracts, warrants, debt securities, and units, from time to time at prices and on terms to be determined at the time of sale.

On June 1, 2020, the Company issued 22,044 shares of common stock to the public at a purchase price of $4.50 per share and pre-funded warrants to purchase 3,511 shares of common stock at a purchase of $4.49 per pre-funded warrant, for total net proceeds to the Company of $108,096 million after deducting underwriting discounts and commissions and other offering expenses. Each pre-funded warrant is exercisable subject to conditions in the warrant agreement into 1 share of common stock at an exercise price of $0.01 per share. All warrants issued in this offering remain outstanding at December 31, 2020.

Note 8 - Stock-based Compensation

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Text Block]

Note 8 — Stock-Based Compensation

As of December 31, 2020, the Company had three stock-based employee compensation plans, the Amended and Restated Stock Incentive Plan (“Incentive Plan”), the Amended and Restated Inducement Equity Incentive Plan (“Inducement Plan”) and the Employee Stock Purchase Plan (“ESPP”). The Incentive Plan was amended and restated on March 19, 2020 and approved by the Company’s stockholders on May 12, 2020. The Inducement Plan was adopted by the Board of Directors on April 24, 2019 and amended and restated by the Board of Directors in February 2020 and in July 2020. The ESPP was amended and restated in March 2020 and approved by the Company’s stockholders on May 12, 2020. Stock-based compensation expense of $14,794 ($12,938 of expense related to the Incentive Plan, $1,494 of expense related to the Inducement Plan, $362 of expense related to the ESPP) was recognized during 2020, while $17,719 ($17,164 of expense related to the Incentive Plan, $323 of expense related to the Inducement Plan, $232 of expense related to the ESPP) was recognized during 2019 and $9,396 ($9,223 of expense related to the Incentive Plan, $173 of expense related to the ESPP) was recognized during 2018.

The Company accounts for stock-based compensation in accordance with FASB authoritative guidance regarding share-based payments. Total stock-based compensation was allocated as follows:

	Year Ended December 31,
	2020		2019		2018
Research and development	$	10,222	$	13,977	$	6,867
Selling, general and administrative		4,572		3,742		2,529
Total stock-based compensation expense	$	14,794	$	17,719	$	9,396

Stock Incentive Plan

The Company grants stock option awards and restricted stock unit awards to its employees, directors, and consultants under the Incentive Plan. Under the Incentive Plan, stock option awards are granted with an exercise price equal to the market price of the Company’s stock at the date of grant. Commencing March 1, 2011, stock option awards and restricted stock units granted to employees generally vest 25% each year until fully vested after four years. In August 2013, December 2014 and December 2019, the Company issued 1,032, 1,250 and 315 performance-based stock options, respectively. These awards vest upon successful completion of specific development milestones. As of December 31, 2020, 100%, 85% and 100% of the August 2013, December 2014 and December 2019 grants, respectively, have vested. During 2020, the Company recognized $1,768 and $684 of stock compensation expense related to milestones within the August 2013 and December 2019 grants for which achievement became probable. Stock option awards granted to non-employee directors of the Company generally vest over one year. All stock option awards have contractual terms of 10 years. The vesting exercise provisions of all awards granted under the Incentive Plan are subject to acceleration in the event of certain stockholder-approved transactions, or upon the occurrence of a change in control as defined in the Incentive Plan.

Related activity under the Incentive Plan is as follows:

							Weighted
							Average
	*Awards*			*Options*			*Exercise*
	*Available*			*Outstanding*			*Price*
Balance at December 31, 2017		468			14,452		$	6.06
Plan amendment		4,400			−			−
Restricted stock awards granted		(13	)		−			−
Stock option awards granted		(4,272	)		4,272			7.15
Stock option awards exercised		−			(1,011	)		2.92
Stock option awards cancelled		222			(222	)		7.44
Balance at December 31, 2018		805			17,491			6.49
Plan amendment		4,000			−			−
Restricted stock awards granted		(27	)		−			−
Stock option awards granted		(4,511	)		4,511			3.91
Stock option awards exercised		−			(251	)		3.75
Stock option awards cancelled		701			(701	)		6.82
Balance at December 31, 2019		968			21,050			5.96
Plan amendment		8,000			−			−
Restricted stock awards granted		(31	)		−			−
Stock option awards granted		(7,469	)		7,469			8.06
Stock option awards exercised		−			(510	)		3.56
Stock option awards cancelled		3,124			(3,124	)		6.93
Balance at December 31, 2020		4,592			24,885		$	6.52

For stock option awards granted under the Incentive Plan during 2020, 2019, and 2018, the fair value was estimated on the date of grant using a Black-Scholes option pricing model and the assumptions noted in the table below. The weighted average grant date fair value of these awards granted during 2020, 2019, and 2018 was $5.48, $2.63, and $4.92, respectively. The fair value of the stock option awards is amortized to expense over the vesting periods using a straight-line expense attribution method.

Inducement Equity Incentive Plan

The Company has the ability to grant stock option awards to newly-hired employees as inducements material to each employee entering employment with the Company. Stock option awards granted to newly hired employees generally vest 25% each year until fully vested after four years. Each stock option has a term of 10 years and is subject to the terms and conditions of the Inducement Plan. The vesting and exercise provisions of all awards granted under the Inducement Plan are subject to acceleration in the event of certain stockholder-approved transactions, or upon the occurrence of a change in control as defined in the Inducement Plan.

Related activity under the Inducement Plan is as follows:

							Weighted
							Average
	*Awards*			*Options*			*Exercise*
	*Available*			*Outstanding*			*Price*
Balance at December 31, 2019		171			1,329		$	3.60
Plan amendment		2,900			−			−
Stock option awards granted		(3,002	)		3,002			4.02
Stock option awards cancelled		160			(160	)		4.15
Balance at December 31, 2020		229			4,171		$	3.88

For stock option awards granted under the Inducement Plan during 2020 and 2019, the fair value was estimated on the date of grant using a Black-Scholes option pricing model and the assumptions noted in the table below. The weighted average grant date fair value of these awards granted during 2020 and 2019 was $2.73 and $2.41, respectively. The fair value of the stock option awards is amortized to expense over the vesting periods using a straight-line expense attribution method.

The following table summarizes the key assumptions used by the Company to value the stock option awards granted under all plans during 2020, 2019, and 2018, respectively. The expected life is based on the average of the assumption that all outstanding stock option awards will be exercised at full vesting and the assumption that all outstanding stock option awards will be exercised at the midpoint of the current date (if already vested) or at full vesting (if not yet vested) and the full contractual term. The expected volatility represents the historical volatility on the Company’s publicly traded common stock. The Company has assumed no expected dividend yield, as dividends have never been paid to stock or option holders and will not be paid for the foreseeable future. The weighted average risk-free interest rate is the implied yield currently available on zero-coupon government issues with a remaining term equal to the expected term.

Weighted Average Assumptions for Stock Option Awards Granted to Employees and Directors under the Plans

	2020			2019			2018
Expected Life		5.5			5.5			5.5
Expected Volatility		84	%		81	%		82	%
Expected Dividend Yield		0.0	%		0.0	%		0.0	%
Risk-Free Interest Rate		0.4	%		1.8	%		2.7	%

The total intrinsic value of stock option awards exercised under the Incentive Plan was $1,562 during 2020, $1,127 during 2019, and $4,504 during 2018. The intrinsic value represents the total proceeds (fair market value at the date of exercise, less the exercise price, times the number of stock option awards exercised) received by all individuals who exercised stock option awards during the period. No stock option awards were exercised under the Inducement Plan in 2020.

The following table summarizes, at December 31, 2020, by price range: (1) for stock option awards outstanding under the Incentive Plan, the number of stock option awards outstanding, their weighted average remaining life and their weighted average exercise price; and (2) for stock option awards exercisable under the Plan, the number of stock option awards exercisable and their weighted average exercise price:

					Outstanding					Exercisable
						Weighted		Weighted				Weighted
						Average		Average				Average
						Remaining		Exercise				Exercise
Range				Number		Life		Price		Number		Price

$	0	to	3		2,514		6.1	$	2.19		1,414	$	1.25
	3	to	6		12,689		7.0		4.22		6,854		2.48
	6	to	9		10,852		9.2		7.88		2,005		4.89
	9	to	12		2,347		4.5		10.85		2,129		4.51
	12	to	15		559		4.1		12.30		539		6.43
	15	to	18		95		4.5		15.39		95		10.57
$	0	to	18		29,056		7.5	$	6.14		13,036	$	3.27

The weighted average remaining contractual life of stock option awards exercisable under the plans at December 31, 2020 was 5.3 years.

The aggregate intrinsic value of stock option awards outstanding and exercisable under the plans at December 31, 2020 was $29,716. The aggregate intrinsic value represents the value (the period’s closing market price, less the exercise price, times the number of in-the-money stock option awards) that would have been received by all stock option award holders under the plans had they exercised their stock option awards at the end of the year.

The total fair value of the stock option awards vested under the plans was $18,739 during 2020, $12,499 during 2019, and $8,952 during 2018.

As of December 31, 2020, the number of stock option awards vested and expected to vest under the plans is 26,487. The weighted average exercise price of these stock option awards is $6.13 and their weighted average remaining contractual life is 7.4 years.

The following table summarizes the changes in the number and weighted-average grant-date fair value of non-vested stock option awards during 2020:

	Non-Vested Stock Option Awards			Weighted Average Grant-Date Fair Value
Balance December 31, 2019		11,688		$	3.77
Stock option awards granted		10,471			4.69
Stock option awards vested		(4,543	)		4.12
Stock option awards forfeited		(1,596	)		3.96
Balance December 31, 2020		16,020		$	4.25

As of December 31, 2020, there was approximately $56,094 of total unrecognized compensation cost related to non-vested employee stock option awards granted by the Company. That cost is expected to be recognized as follows: $17,758 in 2021, $16,281 in 2022, $12,484 in 2023, and $9,571 in 2024.

Employee Stock Purchase Plan

The Company has reserved a total of 4,475 shares of common stock to be purchased under the ESPP, of which 2,873 shares remain available for purchase at December 31, 2020. Eligible employees may authorize up to 15% of their salary to purchase common stock at the lower of 85% of the beginning or 85% of the ending price during six-month purchase intervals. No more than 3 shares may be purchased by any one employee at the six-month purchase dates and no employee may purchase stock having a fair market value at the commencement date of $25 or more in any one calendar year.

There were 246, 115, and 92 shares of common stock purchased under the ESPP in 2020, 2019, and 2018, respectively, at a weighted average price per share of $2.56, $3.51, and $3.83, respectively. Expense of $362, $232, and $173 related to the ESPP was recognized during 2020, 2019, and 2018, respectively. Compensation expense for shares purchased under the ESPP related to the purchase discount and the “look-back” option were determined using a Black-Scholes option pricing model. The weighted average grant date fair values of shares granted under the ESPP during 2020, 2019, and 2018, were $1.47, $2.01, and $1.89, respectively.

Note 9 - Income Taxes

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Text Block]

Note 9 — Income Taxes

The Company has incurred net losses since inception and, consequently, has not recorded any U.S. Federal and state income tax expense or benefit.

The components of loss before provision for income taxes were as followings:

	2020
Domestic	$	(176,613	)
Foreign		(6,201	)
Loss before provision for income taxes	$	(182,814	)

The differences between the Company’s effective tax rate and the statutory tax rate in 2020, 2019, and 2018, are as follows:

	2020			2019			2018
Income tax benefit at federal statutory rate (21% for 2020, 2019 and 2018)	$	(38,391	)	$	(22,868	)	$	(21,263	)
State and local income taxes net of federal tax benefit		(2,544	)		(1,591	)		(2,547	)
Permanent items		774			691			503
Rate change		(82	)		625			(29	)
Expiration of attribute carryforwards		3,774			3,976			2,183
Research and development tax credits		(4,080	)		(4,938	)		(4,905	)
Foreign rate differential		542			-			-
Other		1,456			281			18
Change in valuation allowance		38,551			23,824			26,040
Income tax expense	$	-		$	-		$	-

The Company recognizes the impact of a tax position in its financial statements if it is more likely than not that the position will be sustained on audit based on the technical merits of the position. The Company has concluded that it has an uncertain tax position pertaining to its research and development and orphan drug credit carryforwards. The Company has established these credits based on information and calculations it believes are appropriate and the best estimate of the underlying credit. Any changes to the Company’s unrecognized tax benefits are offset by an adjustment to the valuation allowance and there would be no impact on the Company’s financial statements. The Company does not expect its unrecognized tax benefits to change significantly over the next 12 months.

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:

	2020		2019
Balance at January 1,	$	7,210	$	5,976
Additions to current period tax positions		1,020		1,234
Additions to prior period tax positions		−		−
Reductions to prior period tax provisions		−		−
Balance at December 31,	$	8,230	$	7,210

The Company’s ability to utilize the net operating loss and tax credit carryforwards in the future may be subject to substantial restrictions in the event of past or future ownership changes as defined in Section 382 of the Internal Revenue Code of 1986, as amended and similar state tax law.

Significant components of the Company’s deferred tax assets and liabilities are as follows:

	2020			2019
Deferred tax assets:
Net federal and state operating losses	$	159,939		$	155,190
Research and development credits		66,331			63,275
Royalty income		28,034			-
Stock-based compensation		10,732			9,786
Leasing obligations		1,135			1,070
Other		5,563			3,801
Total deferred tax assets		271,734			233,122
Deferred tax liabilities:
Fixed assets		(124	)		(114	)
Right of use asset		(854	)		(803	)
Total deferred tax liabilities		(978	)		(917	)
Valuation allowance		(270,756	)		(232,205	)
Net deferred tax assets	$	−		$	−

The majority of the Company’s deferred tax assets relate to net operating loss and research and development carryforwards that can only be realized if the Company is profitable in future periods. It is uncertain whether the Company will realize any tax benefit related to these carryforwards. Accordingly, the Company has provided a full valuation allowance against the net deferred tax assets due to uncertainties as to their ultimate realization. The valuation allowance will remain at the full amount of the deferred tax assets until it is more likely than not that the related tax benefits will be realized. The Company’s valuation allowance increased by $38,551, $23,824, and $26,040 in 2020, 2019, and 2018, respectively.

As of December 31, 2020, the Company had U.S. federal operating loss carryforwards of $677,109, state operating loss carryforwards of $494,608, foreign net operating losses of $6,427, and U.S. research and development and orphan drug credit carryforwards of $74,561, which will expire at various dates from 2021 through 2040. Federal losses, state losses, research and development credit carryforwards began expiring in 2020. The foreign net operating losses have an indefinite carryforward period.

Tax years 2017-2020 remain open to examination by the major taxing jurisdictions to which the Company is subject. Additionally, years prior to 2017 are also open to examination to the extent of loss and credit carryforwards from those years. The Company recognizes interest and penalties accrued related to unrecognized tax benefits as components of its income tax provision. However, there were no provisions or accruals for interest and penalties in 2020, 2019 and 2018.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Note 10 - Employee 401(k) Plan

12 Months Ended

Dec. 31, 2020

Retirement Benefits [Text Block]

Note 10 — Employee 401(k) Plan

In January 1991, the Company adopted an employee retirement plan (“401(k) Plan”) under Section 401(k) of the Internal Revenue Code covering all employees. Employee contributions may be made to the 401(k) Plan up to limits established by the Internal Revenue Service. Company matching contributions may be made at the discretion of the Board of Directors. The Company made matching contributions of $1,569, $926, and $724 in 2020, 2019, and 2018, respectively.

The entire disclosure for retirement benefits.

+ References

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+ Details

Note 11 - Collaborative and Other Research and Development Contracts

12 Months Ended

Dec. 31, 2020

Collaborative Arrangement Disclosure [Text Block]

Note 11 — Collaborative and Other Research and Development Contracts

National Institute of Allergy and Infectious Diseases (“NIAID/HHS”). In September 2013, NIAID/HHS contracted with the Company for the development of galidesivir as a treatment for Marburg virus disease and subsequently, Yellow Fever and Ebola virus disease. As of December 31, 2020, all options under this contract have been awarded, and the total value of the contract, as amended, is $45,931, inclusive of the $2,897 added to the contract in August 2020 to support the development of galidesivir. In August 2020, NIAID/HHS awarded the Company a new contract, with potential aggregate funding up of to $43,908 if all contract options are exercised, to manufacture and evaluate the safety, efficacy and tolerability of galidesivir. NIAID/HHS made an initial award of $6,326 to the Company under this new contract.

Biomedical Advanced Research and Development Authority (“BARDA/HHS”). In March 2015, BARDA/HHS awarded the Company a contract for the continued development of galidesivir as a potential treatment for diseases caused by RNA pathogens, including filoviruses. This BARDA/HHS contract includes a base contract of $16,265 to support galidesivir drug manufacturing, as well as $22,855 in additional development options that can be exercised by the government, bringing the potential value of the contract to $39,120. As of December 31, 2020, a total of $20,574 has been awarded under exercised options within this contract.

The contracts with NIAID/HHS and BARDA/HHS are cost-plus-fixed-fee contracts. That is, the Company is entitled to receive reimbursement for all costs incurred in accordance with the contract provisions that are related to the development of galidesivir plus a fixed fee, or profit. BARDA/HHS and NIAID/HHS will make periodic assessments of progress, and the continuation of the contract is based on the Company’s performance, the timeliness and quality of deliverables, and other factors. The government has rights under certain contract clauses to terminate these contracts. These contracts are terminable by the government at any time for breach or without cause.

U.S. Department of Health and Human Services (“HHS”). In September 2018, HHS awarded the Company a $34,660 contract for the procurement of up to 50,000 doses of RAPIVAB (peramivir injection) over a five-year period, including an initial base order of 10,000 doses. In September 2019, HHS exercised its option to purchase an additional 10,000 doses of RAPIVAB. The Company delivered a total of 20,000 doses of RAPIVAB and approximately $13,864 of product sales in 2019. On September 3, 2020, the Company announced that HHS had exercised an option under this contract to purchase an additional 10,000 doses of RAPIVAB for $6,932, which the Company expects to deliver in 2021. No shipments were delivered in 2020 under this additional 10,000 dose option.

Torii Pharmaceutical Co., Ltd. (“Torii”). On November 5, 2019, the Company entered into a Commercialization and License Agreement with Torii (the “Torii Agreement”), granting Torii the exclusive right to commercialize ORLADEYO™ for the prevention of hereditary angioedema (“HAE”) attacks in Japan.

Under the Torii Agreement, the Company received an upfront, non-refundable payment of $22,000 and is eligible to receive an additional milestone payment of $15,000 upon receipt from Japan’s National Health Insurance System of a reimbursement price approval for ORLADEYO in excess of the threshold specified in the Torii Agreement.

In addition, under the Torii Agreement, the Company is entitled to receive tiered royalty payments, ranging from 20% to 40% of annual net sales of ORLADEYO in Japan during each calendar year. Torii’s royalty payment obligations are subject to customary reductions in certain circumstances, but may not be reduced by more than 50% of the amount that otherwise would have been payable to the Company in the applicable calendar quarter. Torii’s royalty payment obligations commence upon the first commercial sale of ORLADEYO in Japan and expire upon the later of (i) the tenth anniversary of the date of first commercial sale of ORLADEYO in Japan, (ii) the expiration of the Company’s patents covering ORLADEYO, and (iii) the expiration of regulatory exclusivity for ORLADEYO in Japan. The Company will be responsible for supplying Torii with its required amounts of ORLADEYO. The activities of the parties pursuant to the Torii Agreement will be overseen by a joint steering committee, to be composed of an equal number of representatives from each party to coordinate the development and commercialization of ORLADEYO in Japan.

Under the Torii Agreement, the Company has granted Torii a right of first negotiation (“ROFN”) to commercialize ORLADEYO in Japan for the acute treatment of HAE attacks if the Company develops ORLADEYO for such indication and to commercialize any additional kallikrein inhibitor that the Company may develop in the future for use in HAE in Japan. Under both ROFNs, if the parties do not agree to terms with respect to a definitive amendment to the Torii Agreement or new agreement, as applicable, the terms of the amendment or agreement would be set by a third-party arbitrator.

The Company identified performance obligations related to (i) the license to develop and commercialize ORLADEYO, (ii) regulatory approval support and (iii) reimbursement pricing approval support. These were each determined to be distinct from the other performance obligations. The Company allocated the $22,000 upfront consideration to the identified performance obligations using estimation approaches to determine the standalone selling prices under ASC 606. Specifically, in determining the value related to the license, a valuation approach utilizing risk adjusted discounted cash flow projections was used and an expected cost plus margin approach was utilized for the other performance obligations. The Company recognized $20,101 in revenue in 2019 including $19,344 associated with the license which was transferred to Torii at the execution of the Agreement and $757 related to the 2020 services provided in the performance of the two approvals. The remaining $1,899 of the $22,000 upfront payment was recognized as revenue in 2020 as the services were delivered.

Seqirus UK Limited (“SUL”). On June 16, 2015, the Company and SUL, a limited company organized under the laws of the United Kingdom and a subsidiary of CSL Limited, a company organized under the laws of Australia, entered into a License Agreement (the “SUL Agreement”) granting SUL and its affiliates worldwide rights to develop, manufacture and commercialize RAPIVAB (peramivir injection) for the treatment of influenza except for the rights to conduct such activities in Israel, Japan, Korea and Taiwan (the permitted geographies together constituting the “Territory”). Under the terms of the SUL Agreement, the Company received an upfront payment of $33,740 and has achieved all development milestones under the contract totaling $12,000.

On March 4, 2020, the International Court of Arbitration of the International Chamber of Commerce (“ICC Tribunal”) delivered a Partial Arbitration Award (the “Partial Arbitration Award”) in an arbitration matter between the Company and SUL with respect to the SUL Agreement. In the Partial Arbitration Award, the ICC Tribunal found that, during the term, SUL materially breached and abandoned its core duties to the Company under the Diligent Efforts (as defined in the SUL Agreement) requirements of the SUL Agreement as applicable in the U.S. The ICC Tribunal granted a declaratory judgment in favor of the Company terminating the SUL Agreement and restoring all rights to peramivir to the Company. The parties agreed on a transition process for the product, with a full transition of commercialization of the product in the U.S. and Australia returned to the Company as of August 1, 2020 and November 1, 2020, respectively. The ICC Tribunal also awarded the Company its attorneys’ fees and expenses incurred in securing the declaratory judgment as well as the costs incurred by the Company in the arbitration. Finally, the ICC Tribunal found that SUL breached the SUL Agreement by failing to pay the milestone payment due to the Company within 30 days of the approval of peramivir for adult use in the European Union and awarded the Company $5,000 (plus interest) for this claim. The ICC Tribunal retained jurisdiction for further proceedings relating to the award of attorneys’ fees and for any dispute relating to the return to the Company of all rights to peramivir in the Territory. The Company recorded the settlement gain of $8,893 in other income and legal fees and other expenses of $5,026 in selling, general and administrative expenses for the year ended December 31, 2020.

Shionogi & Co., Ltd. (“Shionogi”). In February 2007, the Company entered into an exclusive license agreement with Shionogi to develop and commercialize peramivir in Japan for the treatment of seasonal and potentially life-threatening human influenza. Under the terms of the agreement, Shionogi obtained rights to injectable formulations of peramivir in Japan. The Company developed peramivir under a license from UAB and will owe sublicense payments to UAB on any future milestone payments and/or royalties received by the Company from Shionogi. In October 2008, the Company and Shionogi amended the license agreement to expand the territory covered by the agreement to include Taiwan. Shionogi has commercially launched peramivir under the commercial name RAPIACTA in Japan and Taiwan.

In December 2017, the Company, on behalf of Royalty Sub, instituted arbitration proceedings against Shionogi in order to resolve a dispute with Shionogi under the Shionogi Agreement regarding the achievement of sales milestones and escalating royalties. The arbitration proceedings have concluded, with the decision that no sale milestones had been achieved and that royalties would remain the same. The costs associated with the arbitration proceedings are recoverable from the assets of Royalty Sub in accordance with the terms of the indenture and servicing agreement relating to the PhaRMA Notes.

Green Cross Corporation (“Green Cross”). In June 2006, the Company entered into an agreement with Green Cross to develop and commercialize peramivir in Korea. Under the terms of the agreement, Green Cross will be responsible for all development, regulatory, and commercialization costs in Korea. The Company received a one-time license fee of $250. The license also provides that the Company will share in profits resulting from the sale of peramivir in Korea, including the sale of peramivir to the Korean government for stockpiling purposes. Furthermore, Green Cross will pay the Company a premium over its cost to supply peramivir for development and any future marketing of peramivir products in Korea.

Mundipharma International Holdings Limited (“Mundipharma”). In February 2006, the Company entered into an exclusive, royalty bearing right and license agreement with Mundipharma for the development and commercialization of Mundesine, a Purine Nucleoside Phosphorylase (“PNP”) inhibitor, for use in oncology. The agreement, as amended and restated, provides for the possibility of future event payments totaling $15,000 for achieving specified regulatory events for certain indications and tiered royalties ranging from mid to high single-digit percentages of net product sales in each country where Mundesine is sold by Mundipharma. The Company licensed forodesine and other PNP inhibitors from AECOM/IRL (as defined below) and will owe sublicense payments to AECOM/IRL on all milestone payments and royalties received from Mundipharma.

Albert Einstein College of Medicine of Yeshiva University and Industrial Research, Ltd. (“AECOM” and “IRL” respectively). In June 2000, the Company licensed a series of potent inhibitors of PNP from AECOM and IRL, (together, the “Licensors”). The lead product candidates from this collaboration is forodesine. The Company has obtained worldwide exclusive rights to develop and ultimately distribute these, or any other, product candidates that might arise from research on these inhibitors. The Company has the option to expand the agreement to include other inventions in the field made by the investigators or employees of the Licensors. Under this agreement, as amended and restated, the Company has agreed to use commercially reasonable efforts to develop these drugs and to pay certain milestone payments for each licensed product (which range in the aggregate from $1,400 to almost $4,000 per indication) for future development, single digit royalties on net sales of any resulting product made by the Company, and to share a portion of future payments received from other third-party partners, if any. In addition, the Company has agreed to pay annual license fees, which can range from $150 to $500, that are creditable against actual royalties and other payments due to the Licensors. The Licensors have also granted the Company an exclusive worldwide license of galidesivir for any antiviral use.

The University of Alabama at Birmingham (“UAB”). The Company currently has agreements with UAB for influenza neuraminidase and complement inhibitors. Under the terms of these agreements, UAB performed specific research for the Company in return for research payments and license fees. UAB has granted the Company certain rights to any discoveries in these areas resulting from research developed by UAB or jointly developed by UAB with the Company. The Company has agreed to pay single digit royalties on sales of any resulting product and to share in future payments received from other third-party partners. The Company has completed the research under the UAB agreements. These two agreements each have an initial 25-year term, are automatically renewable for five-year terms throughout the life of the last patent and are terminable by the Company upon three months’ notice and by UAB under certain circumstances. Upon termination both parties shall cease using the other parties’ proprietary and confidential information and materials, the parties shall jointly own joint inventions and UAB shall resume full ownership of all UAB licensed products. There is currently no activity between the Company and UAB on these agreements, but when the Company licenses this technology, such as in the case of the Shionogi and Green Cross, or commercializes products related to these programs, the Company will owe sublicense fees or royalties on amounts received.

Note 12 - Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2020

Quarterly Financial Information [Text Block]

Note 12 — Quarterly Financial Information (Unaudited)

	First			Second			Third			Fourth
2020 Quarters
Revenues	$	4,823		$	2,871		$	6,102		$	4,016
Net Loss		(37,599	)		(38,607	)		(46,115	)		(60,493	)
Basic and diluted net loss per share		(0.24	)		(0.24	)		(0.26	)		(0.34	)
2019 Quarters
Revenues	$	5,887		$	1,448		$	1,775		$	39,725
Net Loss		(31,054	)		(37,629	)		(37,592	)		(2,622	)
Basic and diluted net loss per share		(0.28	)		(0.34	)		(0.34	)		(0.02	)

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Description of Company [Policy Text Block]

The Company

Basis of Accounting, Policy [Policy Text Block]

Basis of Presentation

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash and Cash Equivalents

Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]

Restricted Cash

Investment, Policy [Policy Text Block]

Investments

	December 31, 2020
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	24,986	$	14	$	3	$	(3	)	$	25,000
Certificates of deposit		3,225		11		3		−			3,239
Total Investments	$	28,211	$	25	$	6	$	(3	)	$	28,239

	December 31, 2019
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	10,488	$	50	$	23	$	−		$	10,561
Corporate debt securities		9,742		59		10		(1	)		9,810
Certificates of deposit		1,669		7		7		−			1,683
Total Investments	$	21,899	$	116	$	40	$	(1	)	$	22,054

The Company’s investments at December 31, 2020 and 2019 have maturities of one year or less.

Receivable [Policy Text Block]

Receivables from Collaborations

At December 31, 2020 and December 31, 2019, the Company had the following receivables:

	December 31, 2020
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	−	$	5,402	$	5,402
Shionogi & Co. Ltd.		2,037		4		2,041
Green Cross Corporation		740		21		761
Mundipharma International Holdings Limited		39		−		39
Total receivables	$	2,816	$	5,427	$	8,243

	December 31, 2019
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	1,353	$	15,023	$	16,376
Shionogi & Co. Ltd.		1,336		4		1,340
Green Cross Corporation		2,924		8		2,932
Mundipharma International Holdings Limited		56		-		56
Seqirus UK Limited		1,091		351		1,442
Total receivables	$	6,760	$	15,386	$	22,146

Receivables from Product Sales

Inventory, Policy [Policy Text Block]

Inventory

Property, Plant and Equipment, Policy [Policy Text Block]

Property and Equipment

Intangible Assets, Finite-Lived, Policy [Policy Text Block]

Patents and Licenses

Accrued Expenses [Policy Text Block]

Accrued Expenses

●

fees paid to Clinical Research Organizations (“CROs”) in connection with preclinical and toxicology studies and clinical trials;

	●	fees paid to investigative sites in connection with clinical trials;
	●	fees paid to contract manufacturers in connection with the production of the Company’s raw materials, drug substance, drug products, and product candidates; and

●

professional fees.

Accrued expenses were comprised of the following:

	December 31,
	2020		2019
Compensation and benefits	$	11,030	$	6,190
Development costs		15,150		11,302
Inventory		2,453		29
Professional fees		333		326
Duties and taxes		80		67
Other		4,896		3,451
Total accrued expenses	$	33,942	$	21,365

Income Tax, Policy [Policy Text Block]

Income Taxes

Comprehensive Income, Policy [Policy Text Block]

Accumulated Other Comprehensive Loss

Revenue [Policy Text Block]

Revenue Recognition

Collaborative and Other Research and Development Arrangements and Royalties

Product Sales

The Company recorded the following revenues for the years ended December 31:

	2020		2019		2018
Product sales, net	$	3,301	$	17,533	$	−
Royalty revenue		3,381		6,303		6,101
Collaborative and other research and development revenues:
U.S. Department of Health and Human Services		9,231		4,898		2,552
Torii Pharmaceutical Co., Ltd.		1,899		20,101		−
Seqirus UK Limited		−		−		12,000
Total collaborative and other research and development revenues		11,130		24,999		14,552
Total revenues	$	17,812	$	48,835	$	20,653

Advertising

Research and Development Expense, Policy [Policy Text Block]

Research and Development Expenses

Share-based Payment Arrangement [Policy Text Block]

Stock-Based Compensation

Interest Expense and Royalty Financing Obligation [Policy Text Block]

Interest Expense and Royalty Financing Obligation

Interest Expense and Deferred Financing Costs [Policy Text Block]

Interest Expense and Deferred Financing Costs

Currency Hedge Agreement [Policy Text Block]

Currency Hedge Agreement

Earnings Per Share, Policy [Policy Text Block]

Net Loss Per Share

Use of Estimates, Policy [Policy Text Block]

Use of Estimates

Concentration of Market Risk [Policy Text Block]

Significant Customers and Other Risks

Significant Customers

Risks from Third Party Manufacturing and Distribution Concentration

Credit Risk

New Accounting Pronouncements, Policy [Policy Text Block]

Recent Accounting Pronouncements

Note 1 - Significant Accounting Policies and Concentrations of Risk (Tables)

12 Months Ended

Dec. 31, 2020

Debt Securities, Available-for-sale [Table Text Block]

	December 31, 2020
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	24,986	$	14	$	3	$	(3	)	$	25,000
Certificates of deposit		3,225		11		3		−			3,239
Total Investments	$	28,211	$	25	$	6	$	(3	)	$	28,239

	December 31, 2019
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	10,488	$	50	$	23	$	−		$	10,561
Corporate debt securities		9,742		59		10		(1	)		9,810
Certificates of deposit		1,669		7		7		−			1,683
Total Investments	$	21,899	$	116	$	40	$	(1	)	$	22,054

Schedule of Receivables from Collaborations [Table Text Block]

	December 31, 2020
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	−	$	5,402	$	5,402
Shionogi & Co. Ltd.		2,037		4		2,041
Green Cross Corporation		740		21		761
Mundipharma International Holdings Limited		39		−		39
Total receivables	$	2,816	$	5,427	$	8,243

	December 31, 2019
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	1,353	$	15,023	$	16,376
Shionogi & Co. Ltd.		1,336		4		1,340
Green Cross Corporation		2,924		8		2,932
Mundipharma International Holdings Limited		56		-		56
Seqirus UK Limited		1,091		351		1,442
Total receivables	$	6,760	$	15,386	$	22,146

Schedule of Accrued Liabilities [Table Text Block]

	December 31,
	2020		2019
Compensation and benefits	$	11,030	$	6,190
Development costs		15,150		11,302
Inventory		2,453		29
Professional fees		333		326
Duties and taxes		80		67
Other		4,896		3,451
Total accrued expenses	$	33,942	$	21,365

Disaggregation of Revenue [Table Text Block]

	2020		2019		2018
Product sales, net	$	3,301	$	17,533	$	−
Royalty revenue		3,381		6,303		6,101
Collaborative and other research and development revenues:
U.S. Department of Health and Human Services		9,231		4,898		2,552
Torii Pharmaceutical Co., Ltd.		1,899		20,101		−
Seqirus UK Limited		−		−		12,000
Total collaborative and other research and development revenues		11,130		24,999		14,552
Total revenues	$	17,812	$	48,835	$	20,653

Note 2 - Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Table Text Block]

	2020			2019
Furniture and fixtures	$	722		$	602
Office equipment		211			184
Software		1,159			1,159
Laboratory equipment		3,774			3,462
Leasehold improvements		8,583			8,528
		14,449			13,935
Less accumulated depreciation and amortization		(7,336	)		(6,588	)
Property and equipment, net	$	7,113		$	7,347

Note 6 - Lease Obligations and Other Contingencies (Tables)

12 Months Ended

Dec. 31, 2020

Lessee, Lease, Liability, Maturity [Table Text Block]

Remaining Maturities of Lease Liabilities
Year Ending December 31,	Operating Leases
2021	$	1,302
2022		758
2023		619
2024		577
2025		582
Thereafter		7,327
Total lease payments		11,165
Less imputed interest		6,115
Total	$	5,050

Note 8 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	Year Ended December 31,
	2020		2019		2018
Research and development	$	10,222	$	13,977	$	6,867
Selling, general and administrative		4,572		3,742		2,529
Total stock-based compensation expense	$	14,794	$	17,719	$	9,396

Share-based Payment Arrangement, Activity [Table Text Block]

							Weighted
							Average
	*Awards*			*Options*			*Exercise*
	*Available*			*Outstanding*			*Price*
Balance at December 31, 2017		468			14,452		$	6.06
Plan amendment		4,400			−			−
Restricted stock awards granted		(13	)		−			−
Stock option awards granted		(4,272	)		4,272			7.15
Stock option awards exercised		−			(1,011	)		2.92
Stock option awards cancelled		222			(222	)		7.44
Balance at December 31, 2018		805			17,491			6.49
Plan amendment		4,000			−			−
Restricted stock awards granted		(27	)		−			−
Stock option awards granted		(4,511	)		4,511			3.91
Stock option awards exercised		−			(251	)		3.75
Stock option awards cancelled		701			(701	)		6.82
Balance at December 31, 2019		968			21,050			5.96
Plan amendment		8,000			−			−
Restricted stock awards granted		(31	)		−			−
Stock option awards granted		(7,469	)		7,469			8.06
Stock option awards exercised		−			(510	)		3.56
Stock option awards cancelled		3,124			(3,124	)		6.93
Balance at December 31, 2020		4,592			24,885		$	6.52

							Weighted
							Average
	*Awards*			*Options*			*Exercise*
	*Available*			*Outstanding*			*Price*
Balance at December 31, 2019		171			1,329		$	3.60
Plan amendment		2,900			−			−
Stock option awards granted		(3,002	)		3,002			4.02
Stock option awards cancelled		160			(160	)		4.15
Balance at December 31, 2020		229			4,171		$	3.88

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	2020			2019			2018
Expected Life		5.5			5.5			5.5
Expected Volatility		84	%		81	%		82	%
Expected Dividend Yield		0.0	%		0.0	%		0.0	%
Risk-Free Interest Rate		0.4	%		1.8	%		2.7	%

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable [Table Text Block]

					Outstanding					Exercisable
						Weighted		Weighted				Weighted
						Average		Average				Average
						Remaining		Exercise				Exercise
Range				Number		Life		Price		Number		Price

$	0	to	3		2,514		6.1	$	2.19		1,414	$	1.25
	3	to	6		12,689		7.0		4.22		6,854		2.48
	6	to	9		10,852		9.2		7.88		2,005		4.89
	9	to	12		2,347		4.5		10.85		2,129		4.51
	12	to	15		559		4.1		12.30		539		6.43
	15	to	18		95		4.5		15.39		95		10.57
$	0	to	18		29,056		7.5	$	6.14		13,036	$	3.27

Share-based Payment Arrangement, Option, Activity [Table Text Block]

	Non-Vested Stock Option Awards			Weighted Average Grant-Date Fair Value
Balance December 31, 2019		11,688		$	3.77
Stock option awards granted		10,471			4.69
Stock option awards vested		(4,543	)		4.12
Stock option awards forfeited		(1,596	)		3.96
Balance December 31, 2020		16,020		$	4.25

Note 9 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]

	2020
Domestic	$	(176,613	)
Foreign		(6,201	)
Loss before provision for income taxes	$	(182,814	)

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	2020			2019			2018
Income tax benefit at federal statutory rate (21% for 2020, 2019 and 2018)	$	(38,391	)	$	(22,868	)	$	(21,263	)
State and local income taxes net of federal tax benefit		(2,544	)		(1,591	)		(2,547	)
Permanent items		774			691			503
Rate change		(82	)		625			(29	)
Expiration of attribute carryforwards		3,774			3,976			2,183
Research and development tax credits		(4,080	)		(4,938	)		(4,905	)
Foreign rate differential		542			-			-
Other		1,456			281			18
Change in valuation allowance		38,551			23,824			26,040
Income tax expense	$	-		$	-		$	-

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

	2020		2019
Balance at January 1,	$	7,210	$	5,976
Additions to current period tax positions		1,020		1,234
Additions to prior period tax positions		−		−
Reductions to prior period tax provisions		−		−
Balance at December 31,	$	8,230	$	7,210

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	2020			2019
Deferred tax assets:
Net federal and state operating losses	$	159,939		$	155,190
Research and development credits		66,331			63,275
Royalty income		28,034			-
Stock-based compensation		10,732			9,786
Leasing obligations		1,135			1,070
Other		5,563			3,801
Total deferred tax assets		271,734			233,122
Deferred tax liabilities:
Fixed assets		(124	)		(114	)
Right of use asset		(854	)		(803	)
Total deferred tax liabilities		(978	)		(917	)
Valuation allowance		(270,756	)		(232,205	)
Net deferred tax assets	$	−		$	−

Note 12 - Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2020

Quarterly Financial Information [Table Text Block]

	First			Second			Third			Fourth
2020 Quarters
Revenues	$	4,823		$	2,871		$	6,102		$	4,016
Net Loss		(37,599	)		(38,607	)		(46,115	)		(60,493	)
Basic and diluted net loss per share		(0.24	)		(0.24	)		(0.26	)		(0.34	)
2019 Quarters
Revenues	$	5,887		$	1,448		$	1,775		$	39,725
Net Loss		(31,054	)		(37,629	)		(37,592	)		(2,622	)
Basic and diluted net loss per share		(0.28	)		(0.34	)		(0.34	)		(0.02	)

Note 1 - Significant Accounting Policies and Concentrations of Risk (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted Cash and Cash Equivalents, Current, Total	$ 2,221,000	$ 2,221,000	$ 1,551,000
Inventory, Raw Materials, Gross, Total	206,000	206,000
Inventory, Work in Process, Gross	2,555,000	2,555,000
Inventory, Finished Goods, Gross, Total	4,548,000	4,548,000	276,000
Inventory Valuation Reserves, Ending Balance	270,000	270,000	276,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		1,000	0
Advertising Expense		6,567	0	$ 0
Interest Expense, Debt, Total		14,501,000	11,892,000	9,176,000
Amortization of Debt Financing Costs and Original Issue Discounts		$ 1,217,000	$ 1,278,000	$ 885,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)		14,957	2,805	2,274
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivative, Loss on Derivative		$ 632,000	$ 347,000	$ 1,049,000
Derivative, Gain on Derivative		$ 662,000	863,000	$ 941,000
Computer Equipment [Member]
Property, Plant and Equipment, Useful Life (Year)		3 years
Laboratory Equipment, Office Equipment and Software [Member]
Property, Plant and Equipment, Useful Life (Year)		5 years
Furniture and Fixtures [Member]
Property, Plant and Equipment, Useful Life (Year)		7 years
Collaboration Receivables [Member]
Accounts Receivable, Allowance for Credit Loss, Ending Balance	0	$ 0	0
Trade Accounts Receivable [Member]
Accounts Receivable, Allowance for Credit Loss, Ending Balance	0	0
Accounts Receivable, after Allowance for Credit Loss, Total			0
Trade Accounts Receivable [Member] \| RAPIVAB [Member]
Accounts Receivable, after Allowance for Credit Loss, Total	254,000	254,000
Trade Accounts Receivable [Member] \| ORLADEYO [Member]
Accounts Receivable, after Allowance for Credit Loss, Total	149,000	$ 149,000
Maximum [Member]
Maturity Period of High Quality Marketable Securities (Year)		3 years
Average Maturity Period of High Quality Marketable Securities (Month)		18 months
Maturity Period of Short Term Investment (Month)		12 months
Average Maturity for Portfolio Investments (Month)		18 months
Minimum [Member]
Long-term Investment Maturity, Minimum (Month)		12 months
Royalty Receivable [Member]
Restricted Cash and Cash Equivalents, Current, Total	796,000	$ 796,000	134,000
Collateral for Credit [Member]
Restricted Cash and Cash Equivalents, Current, Total	1,425,000	1,425,000	$ 1,417,000
Senior Credit Facility [Member] \| MidCap Financial Services, LLC [Member]
Line of Credit Facility, Remaining Borrowing Capacity	75,000,000	75,000,000
Write off of Deferred Debt Issuance Cost	$ 1,211,000	$ 1,211,000

Note 1 - Significant Accounting Policies and Concentrations of Risk - Fair Value of the Company's Investments by Type (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Amortized Cost	$ 28,211	$ 21,899
Accrued Interest	25	116
Estimated Fair Value	28,239	22,054
Gross Unrealized Gains	6	40
Gross Unrealized Losses		(1)
US Government Agencies Debt Securities [Member]
Amortized Cost	24,986	10,488
Accrued Interest	14	50
Estimated Fair Value	25,000	10,561
Gross Unrealized Gains		23
Certificates of Deposit [Member]
Amortized Cost	3,225	1,669
Accrued Interest	11	7
Estimated Fair Value	3,239	1,683
Gross Unrealized Gains	$ 3	7
Corporate Debt Securities [Member]
Amortized Cost		9,742
Accrued Interest		59
Estimated Fair Value		9,810
Gross Unrealized Gains		10
Gross Unrealized Losses		$ (1)

Note 1 - Significant Accounting Policies and Concentrations of Risk - Summary of Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Receivables	$ 8,243	$ 22,146
Billed Revenues [Member]
Receivables	2,816	6,760
Unbilled Revenues [Member]
Receivables	5,427	15,386
US Department of Health and Human Services [Member]
Receivables	5,402	16,376
US Department of Health and Human Services [Member] \| Billed Revenues [Member]
Receivables		1,353
US Department of Health and Human Services [Member] \| Unbilled Revenues [Member]
Receivables	5,402	15,023
Shionogi and Co. Ltd [Member]
Receivables	2,041	1,340
Shionogi and Co. Ltd [Member] \| Billed Revenues [Member]
Receivables	2,037	1,336
Shionogi and Co. Ltd [Member] \| Unbilled Revenues [Member]
Receivables	4	4
Green Cross Corporation [Member]
Receivables	761	2,932
Green Cross Corporation [Member] \| Billed Revenues [Member]
Receivables	740	2,924
Green Cross Corporation [Member] \| Unbilled Revenues [Member]
Receivables	21	8
Mundipharma International Holdings Limited [Member]
Receivables	39	56
Mundipharma International Holdings Limited [Member] \| Billed Revenues [Member]
Receivables	$ 39	56
Seqirus UK Limited [Member]
Receivables		1,442
Seqirus UK Limited [Member] \| Billed Revenues [Member]
Receivables		1,091
Seqirus UK Limited [Member] \| Unbilled Revenues [Member]
Receivables		$ 351

Note 1 - Significant Accounting Policies and Concentrations of Risk - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Compensation and benefits	$ 11,030	$ 6,190
Development costs	15,150	11,302
Inventory	2,453	29
Professional fees	333	326
Duties and taxes	80	67
Other	4,896	3,451
Total accrued expenses	$ 33,942	$ 21,365

Note 1 - Significant Accounting Policies and Concentrations of Risk - Summary of Revenues (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues	$ 4,016,000	$ 6,102,000	$ 2,871,000	$ 4,823,000	$ 39,725,000	$ 1,775,000	$ 1,448,000	$ 5,887,000	$ 17,812,000	$ 48,835,000	$ 20,653,000
Torii Pharmaceutical Co. [Member]
Revenues										20,101,000
Product [Member]
Revenues									3,301,000	17,533,000
Royalty [Member]
Revenues									3,381,000	6,303,000	6,101,000
Collaborative and Other Research and Development [Member]
Revenues									11,130,000	24,999,000	14,552,000
Collaborative and Other Research and Development [Member] \| US Department of Health and Human Services [Member]
Revenues									9,231,000	4,898,000	2,552,000
Collaborative and Other Research and Development [Member] \| Torii Pharmaceutical Co. [Member]
Revenues									$ 1,899,000	$ 20,101,000
Collaborative and Other Research and Development [Member] \| Seqirus UK Limited [Member]
Revenues											$ 12,000

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9038-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130545-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
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+ Details

Note 2 - Property and Equipment (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Depreciation, Depletion and Amortization, Total	$ 748	$ 724	$ 770

Note 2 - Property and Equipment - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property and equipment	$ 14,449	$ 13,935
Less accumulated depreciation and amortization	(7,336)	(6,588)
Property and equipment, net	7,113	7,347
Furniture and Fixtures [Member]
Property and equipment	722	602
Office Equipment [Member]
Property and equipment	211	184
Software Development [Member]
Property and equipment	1,159	1,159
Laboratory Equipment [Member]
Property and equipment	3,774	3,462
Leasehold Improvements [Member]
Property and equipment	$ 8,583	$ 8,528

Note 3 - Royalty Monetizations (Details Textual) $ in Thousands			12 Months Ended
	Dec. 07, 2020 USD ($)	Mar. 09, 2011 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 01, 2020 USD ($)	Nov. 30, 2020 ¥ / $
Proceeds from Issuance of Secured Debt			$ 119,867
Future Royalties Payable			124,717	$ 0
RPI 2019 Intermediate Finance Trust [Member]
Future Royalties Payable			125,000
RPI 2019 Intermediate Finance Trust [Member] \| ORLADEYO [Member]
Royalty Purchase Agreement, Royalties, Percentage of Sublicense Revenue in Other Markets	20.00%
RPI 2019 Intermediate Finance Trust [Member] \| ORLADEYO [Member] \| Annual Net Sales Under $350,000 [Member]
Royalty Purchase Agreement, Royalties, Percentage of Annual Net Sales in Key Territories	8.75%
RPI 2019 Intermediate Finance Trust [Member] \| ORLADEYO [Member] \| Annual Net Sales Between $350,000 and $550,000 [Member]
Royalty Purchase Agreement, Royalties, Percentage of Annual Net Sales in Key Territories	2.75%
RPI 2019 Intermediate Finance Trust [Member] \| ORLADEYO [Member] \| Annual Net Sales Over $550,000 [Member]
Royalty Purchase Agreement, Royalties, Percentage of Annual Net Sales in Key Territories	0.00%
RPI 2019 Intermediate Finance Trust [Member] \| ORLADEYO [Member] \| Annual Net Sales Under $150,000 [Member]
Royalty Purchase Agreement, Royalties, Percentage of Annual Net Sales in Other Markets	20.00%
RPI 2019 Intermediate Finance Trust [Member] \| ORLADEYO [Member] \| Annual Net Sales Between $150,000 and $230,000 [Member]
Royalty Purchase Agreement, Royalties, Percentage of Annual Net Sales in Other Markets	10.00%
RPI 2019 Intermediate Finance Trust [Member] \| ORLADEYO [Member] \| Annual Net Sales Over $230,000 [Member]
Royalty Purchase Agreement, Royalties, Percentage of Annual Net Sales in Other Markets	0.00%
RPI 2019 Intermediate Finance Trust [Member] \| BCX9930 [Member]
Royalty Purchase Agreement, Royalties, Percentage of Global Annual Net Sales	1.00%
RPI 2019 Intermediate Finance Trust [Member] \| Future Royalties Payable [Member]
Interest Payable			2,108
Proceeds from Issuance of Debt	$ 125,000
Debt Issuance Costs, Net, Total			$ 2,370
Debt Instrument, Interest Rate, Effective Percentage			24.00%
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivative, Loss on Derivative			$ 632	347	$ 1,049
Derivative, Gain on Derivative			$ 662	$ 863	$ 941
PhaRMA Notes Member] \| Currency Hedge Agreement [Member]
Derivative, Forward Exchange Rate (in JPY per USD) \| ¥ / $							100
JPR Royalty Sub LLC [Member] \| PhaRMA Notes Member]
Private Placement of Senior Secured Notes		$ 30,000
Debt Instrument, Interest Rate, Stated Percentage		14.00%
Secured Debt, Total						$ 30,000
Interest Payable						$ 20,614
Percentage of Carrying Amount in Excess of Fair Value				3.00%
JPR Royalty Sub LLC [Member] \| PhaRMA Notes Member] \| Fair Value, Inputs, Level 2 [Member]
Notes Payable, Fair Value Disclosure				$ 30,000
JPR Royalty Sub LLC [Member] \| Royalty Monetization [Member]
Debt Instrument, Face Amount		$ 30,000
Proceeds from Issuance of Secured Debt		22,691
Transaction Costs		4,309
Interest Reserve		$ 3,000

Note 4 - Credit Agreement (Details Textual) - USD ($) $ in Thousands			12 Months Ended
	Dec. 07, 2020	Feb. 05, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Repayments of Lines of Credit			$ 52,420		$ 4,025
Interest Expense, Debt, Total			14,501	$ 11,892	9,176
Amortization of Debt Issuance Costs			2,428	$ 1,278	$ 885
MidCap Financial Services, LLC [Member] \| Senior Credit Facility [Member]
Debt Instrument, Face Amount		$ 100,000
Repayments of Lines of Credit	$ 43,298
MidCap Financial Services, LLC [Member] \| Senior Credit Facility [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate		8.00%
Credit Agreement [Member] \| Athyrium [Member]
Debt Instrument, Face Amount	$ 200,000
Debt Instrument, LIBOR Floor	1.75%
Debt Instrument, LIBOR Cap	3.50%
Debt Instrument, Exit Fee, Percentage of Principal	2.00%
Debt Instrument, Commitment Fee Percentage	1.00%
Long-term Debt, Total			$ 125,000
Debt Instrument, Interest Rate, Effective Percentage			12.17%
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net, Total			$ 7,764
Credit Agreement [Member] \| Athyrium [Member] \| Prior to the Second Anniversary [Member]
Debt Instrument, Prepayment Fee, Percentage of Principal Voluntary Payments	102.00%
Debt Instrument, Prepayment Fee, Percentage of Accrued Interest	0.50%
Credit Agreement [Member] \| Athyrium [Member] \| Between the Second and Third Anniversaries [Member]
Debt Instrument, Prepayment Fee, Percentage of Principal Voluntary Payments	2.00%
Credit Agreement [Member] \| Athyrium [Member] \| Between the Third and Fourth Anniversaries [Member]
Debt Instrument, Prepayment Fee, Percentage of Principal Voluntary Payments	1.00%
Credit Agreement [Member] \| Athyrium [Member] \| After Fourth Anniversary [Member]
Debt Instrument, Prepayment Fee, Percentage of Principal Voluntary Payments	0.00%
Credit Agreement [Member] \| Athyrium [Member] \| Term Loan A Drawn [Member]
Debt Instrument, Covenant, Minimum Unrestricted Cash and Cash Equivalents	$ 15,000
Credit Agreement [Member] \| Athyrium [Member] \| Term Loan A and B Drawn [Member]
Debt Instrument, Covenant, Minimum Unrestricted Cash and Cash Equivalents	20,000
Credit Agreement [Member] \| Athyrium [Member] \| Term Loans A, B and C Drawn [Member]
Debt Instrument, Covenant, Minimum Unrestricted Cash and Cash Equivalents	15,000
Credit Agreement [Member] \| Athyrium [Member] \| Term Loans A, B and C Drawn and Cure Right Exercised [Member]
Debt Instrument, Covenant, Minimum Unrestricted Cash and Cash Equivalents	$ 20,000
Credit Agreement [Member] \| Athyrium [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	8.25%
Credit Agreement [Member] \| Athyrium [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| PIK Interest Payment is Made [Member]
Debt Instrument, Basis Spread on Variable Rate	10.25%
Credit Agreement [Member] \| Athyrium [Member] \| Term A Loan [Member]
Proceeds from Issuance of Long-term Debt, Total	$ 125,000
Interest Expense, Debt, Total			925
Amortization of Debt Issuance Costs			$ 131
Credit Agreement [Member] \| Athyrium [Member] \| Term B Loan [Member]
Debt Instrument, Face Amount	25,000
Credit Agreement [Member] \| Athyrium [Member] \| Term C Loan [Member]
Debt Instrument, Face Amount	$ 50,000

Note 5 - Senior Credit Facility (Details Textual) - MidCap Financial Services, LLC [Member] - Senior Credit Facility [Member] - USD ($) $ in Thousands		1 Months Ended	12 Months Ended
	Feb. 05, 2019	Dec. 31, 2020	Dec. 31, 2020
Debt Instrument, Face Amount	$ 100,000
Debt Instrument, Minimum LIBOR	0.50%
Debt Instrument, Term (Month)	30 months
Extinguishment of Debt, Amount		$ 40,000
Payment for Debt Extinguishment or Debt Prepayment Cost		3,298
Write off of Deferred Debt Issuance Cost		$ 1,211	$ 1,211
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	8.00%
Secured Credit Facility, First Tranche [Member]
Debt Instrument, Face Amount	$ 50,000
Repayments of Long-term Debt, Total	30,000
Secured Credit Facility, Second Tranche [Member]
Debt Instrument, Face Amount	30,000
Secured Credit Facility, Third Tranche [Member]
Debt Instrument, Face Amount	$ 20,000

Note 6 - Lease Obligations and Other Contingencies (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Retained Earnings (Accumulated Deficit), Ending Balance	$ (1,023,442)	$ (840,628)
Operating Lease, Weighted Average Remaining Lease Term (Year)	13 years 1 month 6 days
Operating Lease, Weighted Average Discount Rate, Percent	12.70%
Operating Lease, Expense	$ 1,754	1,464
Operating Lease, Payments	1,696	1,457
Operating Lease, Right-of-Use Asset, Accumulated Amortization	2,641	1,386
Accrued Liabilities, Current [Member]
Operating Lease, Liability, Current	1,179	1,377
Other Noncurrent Liabilities [Member]
Operating Lease, Liability, Noncurrent	3,871	3,406
Other Noncurrent Assets [Member]
Operating Lease, Right-of-Use Asset	$ 3,802	$ 3,590
Minimum [Member]
Lessee, Operating Lease, Term of Contract (Year)		1 year
Maximum [Member]
Lessee, Operating Lease, Term of Contract (Year)		5 years
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset			$ 3,621
Operating Lease, Liability, Total			4,822
Accounting Standards Update 2016-02 [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Retained Earnings (Accumulated Deficit), Ending Balance			$ 238

Note 6 - Lease Obligations and Other Contingencies - Remaining Maturities of Lease Liabilities (Details) $ in Thousands	Dec. 31, 2020 USD ($)
2021	$ 1,302
2022	758
2023	619
2024	577
2025	582
Thereafter	7,327
Total lease payments	11,165
Less imputed interest	6,115
Accrued Liabilities, Current and Other Noncurrent Liabilities [Member]
Total	$ 5,050

Note 7 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands					12 Months Ended
	Jun. 01, 2020	Nov. 21, 2019	Nov. 18, 2019	Aug. 06, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Apr. 24, 2020	Nov. 08, 2017
Maximum Aggregate Offering Price								$ 500,000	$ 200,000
Stock Issued During Period, Shares, New Issues (in shares)	22,044		43,621,000	10,455,000
Shares Issued, Price Per Share (in dollars per share)	$ 4.50	$ 1.69	$ 1.45	$ 5.50
Proceeds from Issuance of Common Stock			$ 58,500	$ 53,400	$ 93,279	$ 58,500	$ 53,400
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		11,765,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 0.01
Proceeds from Issuance of Warrants		$ 19,882			$ 14,817	$ 19,882
Proceeds from Issuance or Sale of Equity, Total	$ 108,096,000
Warrants Issued in Public Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	3,511
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 0.01
Class of Warrant or Right, Warrants Issued, Price Per Warrant (in dollars per share)	$ 4.49

Note 8 - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, shares in Thousands	1 Months Ended			12 Months Ended
	Dec. 31, 2019	Dec. 31, 2014	Aug. 31, 2013	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement, Expense				$ 14,794,000	$ 17,719,000	$ 9,396,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)				10,471
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)				$ 4.69
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total				$ 56,094,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Expected to be Recognized Next Year				17,758,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Expected to be Recognized Year Two				16,281,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Expected to be Recognized Year Three				12,484,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Expected to be Recognized Year Four				9,571,000
Incentive Plan [Member]
Share-based Payment Arrangement, Expense				$ 12,938,000	$ 17,164,000	$ 9,223,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)				$ 5.48	$ 2.63	$ 4.92
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value				$ 1,562,000	$ 1,127,000	$ 4,504,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)	968			4,592	968	805	468
Incentive Plan [Member] \| Share-based Payment Arrangement, Option [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Year)				10 years
Incentive Plan [Member] \| Share-based Payment Arrangement, Option [Member] \| Vest 25% Each Year Until Fully Vested [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				25.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)				4 years
Incentive Plan [Member] \| Performance Shares [Member] \| August 2013 [Member]
Share-based Payment Arrangement, Expense				$ 1,768,000
Incentive Plan [Member] \| Performance Shares [Member] \| December 2019 [Member]
Share-based Payment Arrangement, Expense				$ 684,000
Incentive Plan [Member] \| Performance Shares [Member] \| Vest Upon Successful Completion of Specific Development Milestones [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)	315	1,250	1,032
Incentive Plan [Member] \| Performance Shares [Member] \| Vest Upon Successful Completion of Specific Development Milestones [Member] \| August 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				100.00%
Incentive Plan [Member] \| Performance Shares [Member] \| Vest Upon Successful Completion of Specific Development Milestones [Member] \| December 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				85.00%
Incentive Plan [Member] \| Performance Shares [Member] \| Vest Upon Successful Completion of Specific Development Milestones [Member] \| December 2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				100.00%
Inducement Plan [Member]
Share-based Payment Arrangement, Expense				$ 1,494,000	$ 323,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)				4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Year)				5 years 3 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)				$ 2.73	$ 2.41
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)				10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value				$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value				$ 29,716,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)	171			229	171
Inducement Plan [Member] \| Vest 25% Each Year Until Fully Vested [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				25.00%
Inducement Plan [Member] \| Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate				0.00%
Employee Stock Purchase Plan [Member]
Share-based Payment Arrangement, Expense				$ 362,000	$ 232,000	$ 173,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)				4,475
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)				2,873
Percentage of Salary to Purchase Common Stock, Maximum				15.00%
Percentage of Common Stock Shares, Beginning				85.00%
Percentage of Common Stock Shares, Ending				85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee (in shares)				3
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee, Amount				$ 25,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)				246	115	92
Employee Stock Ownership Plan (ESOP), Weighted Average Purchase Price of Shares Purchased (in dollars per share)				$ 2.56	$ 3.51	$ 3.83
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)				$ 1.47	$ 2.01	$ 1.89
Incentive Plan and Inducement Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate				0.00%	0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value				$ 18,739	$ 12,499,000	$ 8,952,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in shares)				26,487
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price (in dollars per share)				$ 6.13
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term (Year)				7 years 4 months 24 days

Note 8 - Stock-Based Compensation - Stock-based Compensation Allocation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Expense	$ 14,794	$ 17,719	$ 9,396
Research and Development Expense [Member]
Share-based Payment Arrangement, Expense	10,222	13,977	6,867
Selling, General and Administrative Expenses [Member]
Share-based Payment Arrangement, Expense	$ 4,572	$ 3,742	$ 2,529

Note 8 - Stock-based Compensation - Stock Plan Activities (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Incentive Plan [Member]
Awards available, beginning balance (in shares)	968	805	468
Options outstanding, beginning balance (in shares)	21,050	17,491	14,452
Weighted average exercise price, beginning balance (in dollars per share)			$ 6.06
Awards available, plan amendment (in shares)	8,000	4,000	4,400
Awards available, Restricted stock awards granted (in shares)	(31)	(27)	(13)
Awards available, stock option awards granted (in shares)	(7,469)	(4,511)	(4,272)
Options outstanding, stock option awards granted (in shares)	7,469	4,511	4,272
Weighted average exercise price, stock option awards granted (in dollars per share)	$ 8.06	$ 3.91	$ 7.15
Options outstanding, stock option awards exercised (in shares)	(510)	(251)	(1,011)
Weighted average exercise price, stock option awards exercised (in dollars per share)	$ 3.56	$ 3.75	$ 2.92
Awards available, stock option awards cancelled (in shares)	3,124	701	222
Options outstanding, stock option awards cancelled (in shares)	(3,124)	(701)	(222)
Weighted average exercise price, stock option awards cancelled (in dollars per share)	$ 6.93	$ 6.82	$ 7.44
Awards available, ending balance (in shares)	4,592	968	805
Options outstanding, ending balance (in shares)	24,885	21,050	17,491
Weighted average exercise price, ending balance (in dollars per share)	$ 6.52	$ 5.96	$ 6.49
Inducement Plan [Member]
Awards available, beginning balance (in shares)	171
Options outstanding, beginning balance (in shares)	1,329
Weighted average exercise price, beginning balance (in dollars per share)	$ 3.60
Awards available, plan amendment (in shares)	2,900
Awards available, stock option awards granted (in shares)	(3,002)
Options outstanding, stock option awards granted (in shares)	3,002
Weighted average exercise price, stock option awards granted (in dollars per share)	$ 4.02
Awards available, stock option awards cancelled (in shares)	160
Options outstanding, stock option awards cancelled (in shares)	(160)
Weighted average exercise price, stock option awards cancelled (in dollars per share)	$ 4.15
Awards available, ending balance (in shares)	229	171
Options outstanding, ending balance (in shares)	4,171	1,329
Weighted average exercise price, ending balance (in dollars per share)	$ 3.88	$ 3.60

Note 8 - Stock-based Compensation - Weighted Average Assumptions for Stock Option Awards Granted to Employees and Directors Under the Plans (Details) - Incentive Plan and Inducement Plan [Member]	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Expected Life (Year)	5 years 6 months	5 years 6 months	5 years 6 months
Expected Volatility	84.00%	81.00%	82.00%
Expected Dividend Yield	0.00%	0.00%	0.00%
Risk-Free Interest Rate	0.40%	1.80%	2.70%

Note 8 - Stock-based Compensation - Number of Stock Option Awards Exercisable and their Weighted Average Exercise Price (Details)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Upper Exercise Price Range (in dollars per share)	$ 18
Outstanding Number (in shares) \| shares	29,056
Outstanding Weighted Average Remaining Life (Year)	7 years 6 months
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 6.14
Exercisable Number (in shares) \| shares	13,036
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 3.27
Exercise Price Range 01 [Member]
Upper Exercise Price Range (in dollars per share)	$ 3
Outstanding Number (in shares) \| shares	2,514
Outstanding Weighted Average Remaining Life (Year)	6 years 1 month 6 days
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 2.19
Exercisable Number (in shares) \| shares	1,414
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 1.25
Exercise Price Range 02 [Member]
Upper Exercise Price Range (in dollars per share)	$ 6
Outstanding Number (in shares) \| shares	12,689
Outstanding Weighted Average Remaining Life (Year)	7 years
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 4.22
Exercisable Number (in shares) \| shares	6,854
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 2.48
Exercise Price Range 03 [Member]
Upper Exercise Price Range (in dollars per share)	$ 9
Outstanding Number (in shares) \| shares	10,852
Outstanding Weighted Average Remaining Life (Year)	9 years 2 months 12 days
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 7.88
Exercisable Number (in shares) \| shares	2,005
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 4.89
Exercise Price Range 04 [Member]
Upper Exercise Price Range (in dollars per share)	$ 12
Outstanding Number (in shares) \| shares	2,347
Outstanding Weighted Average Remaining Life (Year)	4 years 6 months
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 10.85
Exercisable Number (in shares) \| shares	2,129
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 4.51
Exercise Price Range 05 [Member]
Upper Exercise Price Range (in dollars per share)	$ 15
Outstanding Number (in shares) \| shares	559
Outstanding Weighted Average Remaining Life (Year)	4 years 1 month 6 days
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 12.30
Exercisable Number (in shares) \| shares	539
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 6.43
Exercise Price Range 06 [Member]
Upper Exercise Price Range (in dollars per share)	$ 18
Outstanding Number (in shares) \| shares	95
Outstanding Weighted Average Remaining Life (Year)	4 years 6 months
Outstanding Weighted Average Exercise Price (in dollars per share)	$ 15.39
Exercisable Number (in shares) \| shares	95
Exercisable Weighted Average Exercise Price (in dollars per share)	$ 10.57

Note 8 - Stock-based Compensation - Changes in the Number and Weighted-Average Grant-Date Fair Value (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Non-vested stock option awards (in shares) \| shares	11,688
Weighted average grant-date fair value (in dollars per share) \| $ / shares	$ 3.77
Stock option awards granted (in shares) \| shares	10,471
Stock option awards granted (in dollars per share) \| $ / shares	$ 4.69
Stock option awards vested (in shares) \| shares	(4,543)
Stock option awards vested (in dollars per share) \| $ / shares	$ 4.12
Stock option awards forfeited (in shares) \| shares	(1,596)
Stock option awards forfeited (in dollars per share) \| $ / shares	$ 3.96
Non-vested stock option awards (in shares) \| shares	16,020
Weighted average grant-date fair value (in dollars per share) \| $ / shares	$ 4.25

Note 9 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
Note 9 - Income Taxes (Details Textual) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	$ 38,551,000	$ 23,824,000	$ 26,040,000
Open Tax Year	2017 2018 2019
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	$ 0	$ 0	$ 0
Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	74,561
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	677,109,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total	494,608,000
Foreign Tax Authority [Member]
Operating Loss Carryforwards, Total	$ 6,427,000

Note 9 - Income Taxes - Loss Before Provision for Income Taxes (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Domestic	$ (176,613)
Foreign	(6,201)
Loss before provision for income taxes	$ (182,814)

Note 9 - Income Taxes - Differences Between the Company's Effective Tax Rate and the Statutory Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income tax benefit at federal statutory rate (21% for 2020, 2019 and 2018)	$ (38,391)	$ (22,868)	$ (21,263)
State and local income taxes net of federal tax benefit	(2,544)	(1,591)	(2,547)
Permanent items	774	691	503
Rate change	(82)	625	(29)
Expiration of attribute carryforwards	3,774	3,976	2,183
Research and development tax credits	(4,080)	(4,938)	(4,905)
Foreign rate differential	542
Other	1,456	281	18
Change in valuation allowance	38,551	23,824	26,040
Income tax expense	$ 0	$ 0	$ 0

Note 9 - Income Taxes - Differences Between the Company's Effective Tax Rate and the Statutory Tax Rate (Details) (Parentheticals)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income tax benefit at federal statutory rate, percentage	21.00%	21.00%	21.00%

Note 9 - Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Balance	$ 7,210	$ 5,976
Additions to current period tax positions	1,020	1,234
Balance	$ 8,230	$ 7,210

Note 9 - Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Net federal and state operating losses	$ 159,939	$ 155,190
Research and development credits	66,331	63,275
Royalty income	28,034	0
Stock-based compensation	10,732	9,786
Leasing obligations	1,135	1,070
Other	5,563	3,801
Total deferred tax assets	271,734	233,122
Fixed assets	(124)	(114)
Right of use asset	(854)	(803)
Total deferred tax liabilities	(978)	(917)
Valuation allowance	$ (270,756)	$ (232,205)

Note 10 - Employee 401(k) Plan (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 1,569	$ 926	$ 724

Note 11 - Collaborative and Other Research and Development Contracts (Details Textual) - USD ($) $ in Thousands						1 Months Ended			3 Months Ended								6 Months Ended	12 Months Ended			67 Months Ended	69 Months Ended
	Sep. 03, 2020	Mar. 04, 2020	Nov. 05, 2019	Sep. 06, 2018	Jun. 16, 2015	Aug. 31, 2020	Jun. 30, 2006	Jun. 30, 2000	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2020	Mar. 31, 2015	Nov. 11, 2011
Revenue from Contract with Customer, Including Assessed Tax									$ 4,016	$ 6,102	$ 2,871	$ 4,823	$ 39,725	$ 1,775	$ 1,448	$ 5,887		$ 17,812	$ 48,835	$ 20,653
Arbitration Proceedings of SUL Agreement [Member]
Litigation Settlement, Amount Awarded from Other Party		$ 5,000
Arbitration Proceedings of SUL Agreement [Member] \| Other Income [Member]
Gain (Loss) Related to Litigation Settlement, Total																		8,893
Arbitration Proceedings of SUL Agreement [Member] \| Selling, General and Administrative Expenses [Member]
Legal Fees																	$ 5,026
US Department of Health and Human Services [Member]
Collaborative Agreement Contract Value				$ 34,660
Contract Term (Year)				5 years
Proceeds from Collaborators	$ 6,932																		13,864
Torii Pharmaceutical Co. [Member]
Upfront Payments Receivable Amount			$ 22,000
Potential Milestone Payments Receivable if Regulatory Approval Before December 31, 2021			$ 15,000
Maximum Customary Reduction on Royalty Rate			50.00%
Royalty Payments Receivable, Expiration Term From First Commercial (Year)			10 years
Revenue from Contract with Customer, Including Assessed Tax																			20,101
Contract with Customer, Liability, Revenue Recognized																		1,899
Torii Pharmaceutical Co. [Member] \| License [Member]
Revenue from Contract with Customer, Including Assessed Tax																			$ 19,344
Torii Pharmaceutical Co. [Member] \| Service [Member]
Revenue from Contract with Customer, Including Assessed Tax																		757
Torii Pharmaceutical Co. [Member] \| Minimum [Member]
Royalty Rate if Maintains Sakigake Designation			20.00%
Torii Pharmaceutical Co. [Member] \| Maximum [Member]
Royalty Rate if Maintains Sakigake Designation			40.00%
CSL Limited [Member
Proceeds from License Fees Received					$ 33,740
Milestone Payment Received																					$ 12,000
Base Contract [Member]
Government Contract Receivable																							$ 16,265
Additional Development Options [Member]
Government Contract Receivable																							22,855
ASPRBARDA Contract [Member]
Government Contract Receivable																							$ 39,120
Proceeds from awards for Research and Development Contracts																						$ 20,574
Green Cross Corporation [Member]
Proceeds from License Fees Received							$ 250
Mundipharma [Member]
Potential Milestone Payments Receivable																								$ 15,000
AECOM and IRL [Member]
Milestone Payment Minimum								$ 1,400
Milestone Payment Maximum								4,000
Annual License Fee Minimum								150
Annual License Fee Maximum								$ 500
National Institute of Allergy and Infectious Diseases [Member]
Expected Receivable From Awards for Research and Development Contracts																		$ 45,931
Collaborative Agreement Contract, Covenant, Maximum Amount of Funding						$ 43,908
Collaborative Agreement Contract Value						$ 6,326
UAB [Member]
Period of Agreement (Year)																		25 years
Renewable Period of Agreement (Year)																		5 years

Note 12 - Quarterly Financial Information (Unaudited) - Schedule of Quarterly Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues	$ 4,016	$ 6,102	$ 2,871	$ 4,823	$ 39,725	$ 1,775	$ 1,448	$ 5,887	$ 17,812	$ 48,835	$ 20,653
Net Loss	$ (60,493)	$ (46,115)	$ (38,607)	$ (37,599)	$ (2,622)	$ (37,592)	$ (37,629)	$ (31,054)	$ (182,814)	$ (108,897)	$ (101,252)
Basic and diluted net loss per share (in dollars per share)	$ (0.34)	$ (0.26)	$ (0.24)	$ (0.24)	$ (0.02)	$ (0.34)	$ (0.34)	$ (0.28)	$ (1.09)	$ (0.94)	$ (0.98)