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Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2015	Jan. 31, 2016	Jun. 30, 2015
Entity Registrant Name	BIOCRYST PHARMACEUTICALS INC
Entity Central Index Key	0000882796
Trading Symbol	bcrx
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding (in shares)		73,576,471
Entity Public Float			$ 1,078,490,079
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Collaboration Receivables [Member]
ASSETS
Receivables	$ 6,243,000	$ 3,849,000
Trade Accounts Receivable [Member]
ASSETS
Receivables		5,641,000
Deferred Collaborative Revenue [Member]
LIABILITIES AND STOCKHOLDERS’ EQUITY
Deferred revenue	2,163,000	1,481,000
Deferred Product Sales [Member]
LIABILITIES AND STOCKHOLDERS’ EQUITY
Deferred revenue		5,605,000
Cash and cash equivalents	28,899,000	54,540,000
Restricted cash	1,612,000	150,000
Investments	22,664,000	18,232,000
Inventory	1,612,000	683,000
Prepaid expenses and other current assets	4,870,000	6,172,000
Deferred collaboration expense	90,000	76,000
Total current assets	65,990,000	89,343,000
Investments	47,683,000	41,116,000
Property and equipment, net	5,149,000	207,000
Deferred collaboration expense	265,000	177,000
Other assets	5,468,000	6,031,000
Total assets	124,555,000	136,874,000
Accounts payable	9,307,000	2,849,000
Accrued expenses	16,237,000	11,329,000
Interest payable	6,746,000	6,029,000
Non-recourse notes payable	30,000,000	30,000,000
Total current liabilities	64,453,000	57,293,000
Deferred collaboration revenue	9,674,000	3,552,000
Deferred rent	329,000	394,000
Lease financing obligation	2,375
Stockholders’ equity:
Preferred stock, $0.001 par value; shares authorized — 5,000; no shares outstanding	0	0
Common stock, $0.01 par value; shares authorized — 200,000; shares issued and outstanding — 73,355 in 2015 and 71,955 in 2014	734,000	720,000
Additional paid-in capital	558,113,000	542,943,000
Accumulated other comprehensive loss	(206,000)	(130,000)
Accumulated deficit	(510,917,000)	(467,898,000)
Total stockholders’ equity	47,724,000	75,635,000
Total liabilities and stockholders’ equity	$ 124,555,000	$ 136,874,000

Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	73,355,000	71,955,000
Common stock, shares outstanding (in shares)	73,355,000	71,955,000

Consolidated Statements of Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
Product sales, net	$ 6,291	$ 33
Royalty revenue	2,386	3,025	2,562
Collaborative and other research and development	39,580	10,550	14,769
Total revenues	48,257	13,608	17,331
Expenses
Cost of products sold	1,368	1
Research and development	72,758	51,796	41,943
Selling, general and administrative	13,047	7,461	6,007
Royalty	528	121	98
Total operating expenses	87,701	59,379	48,048
Loss from operations	(39,444)	(45,771)	(30,717)
Interest and other income	535	93	93
Interest expense	(5,200)	(4,998)	(4,778)
Gain on foreign currency derivative	1,090	5,487	5,294
Net loss	$ (43,019)	$ (45,189)	$ (30,108)
Basic and diluted net loss per common share (in dollars per share)	$ (0.59)	$ (0.68)	$ (0.55)
Weighted average shares outstanding (in shares)	72,901	66,773	55,216
Unrealized loss on available for sale investments	$ (76)	$ (134)	$ (23)
Comprehensive loss	$ (43,095)	$ (45,323)	$ (30,131)

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
Consolidated Statements of Cash Flows - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Net loss	$ (43,019,000)	$ (45,189,000)	$ (30,108,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, Depletion and Amortization	180,000	177,000	304,000
Loss (gain) on disposal of property and equipment		27,000	(47,000)
Stock-based compensation expense	9,705,000	10,177,000	4,368,000
Amortization of Financing Costs	439,000	439,000	439,000
Change in fair value of foreign currency derivative	564,000	(5,487,000)	(5,294,000)
Changes in operating assets and liabilities:
Receivables	3,247,000	(7,375,000)	2,447,000
Inventory	(929,000)	(683,000)
Prepaid expenses and other assets	1,207,000	(1,943,000)	(620,000)
Deferred collaboration expense	(102,000)	59,000	5,133,000
Accounts payable and accrued expenses	14,393,000	6,818,000	(2,049,000)
Deferred revenue	1,199,000	4,429,000	(1,103,000)
Net cash used in operating activities:	(13,116,000)	(38,551,000)	(26,530,000)
Investing activities:
Acquisition of property and equipment	(5,122,000)	(106,000)	(30,000)
Proceeds from sale of property and equipment			50,000
Change in restricted cash	(1,462,000)	1,000	157,000
Purchases of investments	(53,830,000)	(73,875,000)	(23,974,000)
Sales and maturities of investments	42,410,000	34,000,000	20,330,000
Net cash used in investing activities:	(18,004,000)	(39,980,000)	(3,467,000)
Financing activities:
Sale of common stock, net		106,600,000	23,633,000
Exercise of stock options	5,124,000	4,997,000	1,333,000
Employee stock purchase plan sales	355,000	310,000	124,000
Receipt of foreign currency derivative collateral			5,180,000
Net cash provided by financing activities:	5,479,000	111,907,000	30,270,000
(Decrease) increase in cash and cash equivalents	(25,641,000)	33,376,000	273,000
Cash and cash equivalents at beginning of year	54,540,000	21,164,000	20,891,000
Cash and cash equivalents at end of year	$ 28,899,000	$ 54,540,000	$ 21,164,000

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2012	$ 509	$ 391,611	$ 27	$ (392,601)	$ (454)
Net loss				(30,108)	(30,108)
Other comprehensive loss			(23)		(23)
Exercise of stock options	6	1,327			1,333
Employee stock purchase plan sales	1	123			124
Issuance of common stock	75	23,559			23,634
Stock-based compensation expense		4,368			4,368
Balance at Dec. 31, 2013	591	420,988	4	(422,709)	(1,126)
Net loss				(45,189)	(45,189)
Other comprehensive loss			(134)		(134)
Exercise of stock options	13	4,984			4,997
Employee stock purchase plan sales	1	309			310
Issuance of common stock	115	106,485			106,600
Stock-based compensation expense		10,177			10,177
Balance at Dec. 31, 2014	720	542,943	(130)	(467,898)	75,635
Net loss				(43,019)	(43,019)
Other comprehensive loss			(76)		(76)
Exercise of stock options	14	5,110			5,124
Employee stock purchase plan sales		355			355
Stock-based compensation expense		9,705			9,705
Balance at Dec. 31, 2015	$ 734	$ 558,113	$ (206)	$ (510,917)	$ 47,724

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Consolidated Statements of Stockholders' Equity (Parentheticals) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common Stock [Member]
Exercise of stock options, shares (in shares)	1,359	1,314	348
Employee stock purchase plan sales, shares (in shares)	41	49	89
Issuance of common stock, shares (in shares)		11,500	7,547
Exercise of stock options, shares (in shares)	1,118	1,258	563
Issuance of common stock, shares (in shares)			2,883

Note 1 - Significant Accounting Policies and Concentrations of Risk

12 Months Ended

Dec. 31, 2015

Notes to Financial Statements

Significant Accounting Policies [Text Block]

Note 1 — Significant Accounting Policies and Concentrations of Risk

The Company

BioCryst Pharmaceuticals, Inc. (the “Company”) is a biotechnology company that designs, optimizes and develops novel small molecule drugs that block key enzymes involved in the pathogenesis of diseases. The Company focuses on the treatment of rare diseases in which significant unmet medical needs exist and align with its capabilities and expertise. The Company was incorporated in Delaware in 1986 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. BioCryst has incurred losses and negative cash flows from operations since inception.

Based on its current operating plans, the Company expects it has sufficient liquidity, with its existing cash, restricted cash and investments of $100,858, to continue its planned operations through mid-2017. The Company’s liquidity needs, and ability to address those needs, will largely be determined by the success of its product candidates and key development and regulatory events in the future. In order to continue its operations substantially beyond mid-2017 it will need to: (1) successfully secure or increase U.S. Government funding of its programs, including procurement contracts; (2) out-license rights to certain of its products or product candidates, pursuant to which the Company would receive cash milestones; (3) raise additional capital through equity or debt financings or from other sources; (4) obtain additional product candidate regulatory approvals, which would generate revenue and cash flow; (5) reduce spending on one or more research and development programs; and/or (6) restructure operations. The Company may issue securities through private placement transactions or registered public offerings pursuant to a registration statement filed with the SEC. Additionally, the Company retains the ability to offer for sale approximately $10,000 of securities, including common stock, preferred stock, depositary shares, stock purchase contracts, warrants and units from its effective shelf S-3 registration statement, which it filed with the Securities and Exchange Commission (“SEC”) on November 6, 2013. The Company will continue to incur operating losses and negative cash flows until revenues reach a level sufficient to support ongoing operations.

Basis of Presentation

Beginning in March 2011, the consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, JPR Royalty Sub LLC (“Royalty Sub”). Royalty Sub was formed in connection with a $30,000 financing transaction the Company completed on March 9, 2011. See Note 3, Royalty Monetization, for a further description of this transaction. All intercompany transactions and balances have been eliminated.

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.

Reclassifications

Long term deferred rent as of December 31, 2014 has been reclassified to conform to the 2015 presentation.

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, 2015 reflects $150 the Company is required to maintain in an interest bearing certificate of deposit to serve as collateral for a corporate credit card program, $59 in royalty revenue paid by Shionogi & Co., Ltd. (“Shionogi”) designated for interest on the PhaRMA Notes (defined in Note 3) and $1,403 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, 2015, the Company believes that the costs of its investments are recoverable in all material respects.

The following tables summarize the fair value of the Company’s investments by type. The estimated fair value 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, 2015
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	26,557	$	88	$	—	$	(99	)	$	26,546
Corporate debt securities		21,820		184		—		(41	)		21,963
Certificates of deposit		21,884		21		5		(72	)		21,838
Total investments	$	70,261	$	293	$	5	$	(212	)	$	70,347

	December 31, 2014
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	20,307	$	22	$	—	$	(23	)	$	20,306
Corporate debt securities		27,152		151		5		(47	)		27,261
Commercial paper		11,838		6		—		(63	)		11,781
Total investments	$	59,297	$	179	$	5	$	(133	)	$	59,348

The following table summarizes the scheduled maturity for the Company’s investments at December 31, 2015 and 2014.

	2015		2014
Maturing in one year or less	$	22,664	$	18,232
Maturing after one year through two years		28,395		25,459
Maturing after two years		19,288		15,657
Total investments	$	70,347	$	59,348

Receivable 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 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. At December 31, 2015 and 2014, the Company had the following receivables.

	December 31, 2015
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	—	$	5,536	$	5,536
Shionogi & Co. Ltd.		469		—		469
Seqirus UK Limited		210		28		238
Total receivables	$	679	$	5,564	$	6,243

	December 31, 2014
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	—	$	2,778	$	2,778
Shionogi & Co. Ltd.		1,071		—		1,071
Total receivables	$	1,071	$	2,778	$	3,849

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. These receivables are evaluated to determine if any reserve or allowance should be established at each reporting date.

Inventory

At December 31, 2015 and 2014, the Company’s inventory consisted of RAPIVAB finished goods inventory and work in process. Inventory is stated at the lower of cost, determined under the first-in, first-out (“FIFO”) method, or market. 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 will capitalize subsequent costs related to the production of inventories.

During 2014, in connection with the FDA approval of RAPIVAB, the Company began capitalizing costs associated with the production of RAPIVAB inventories.

The Company’s inventory consisted of the following:

	As of December 31,
	2015		2014
Work in process	$	1,612	$	267
Finished goods		—		416
Net inventories	$	1,612	$	683

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 remaining lease term, whichever is less. Property consists of a leased building which did not meet the sale-leaseback criteria and is recorded at its fair value, less depreciation. The building is being depreciated over a period of ten years equal to the term of the related lease

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, 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 our raw materials, drug substance and drug products; 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.

Accrued expenses were comprised of the following:

	December 31,
	2015		2014
Compensation and benefits	$	424	$	2,105
Development costs		10,398		4,232
Inventory		549		397
Professional fees		242		238
Duties and taxes		102		75
Other		4,522		4,282
Total accrued expenses	$	16,237	$	11,329

As of December 31, 2015 and 2014, the carrying value of accrued expenses approximates their fair value due to their short-term settlement.

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. During 2015, realized gains of $13 were reclassified out of accumulated other comprehensive loss. No reclassifications out of accumulated other comprehensive loss were recorded during 2014.

Revenue Recognition

The Company recognizes revenues from collaborative and other research and development arrangements, royalties and product sales when realized or realizable and earned. Revenue is realized or realizable and earned when all of the following criteria are met: (i) persuasive evidence of an arrangement exists; (ii) delivery has occurred or services have been rendered; (iii) the seller’s price to the buyer is fixed or determinable; and (iv) collectability is reasonably assured.

Collaborative and Other Research and Development Arrangements and Royalties

Revenue from license fees, royalty payments, event 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. Fees received under licensing agreements that are related to future performance are deferred and recognized over an estimated period determined by management based on the terms of the agreement and the products licensed. Revisions to revenue or profit estimates as a result of changes in the estimated revenue period are recognized prospectively.

Under certain of the Company’s license agreements, the Company receives royalty payments based upon its licensees’ net sales of covered products. The Company recognizes royalty revenues when it can reliably estimate such amounts and collectability is reasonably assured.

For arrangements that involve the delivery of more than one element, each product, service and/or right to use assets is evaluated to determine whether it qualifies as a separate unit of accounting. This determination is based on whether the deliverable has “stand-alone value” to the customer. The consideration that is fixed or determinable is then allocated to each separate unit of accounting based on the relative selling price of each deliverable. The estimated selling price of each deliverable is determined using the following hierarchy of values: (i) vendor-specific objective evidence of fair value, (ii) third-party evidence of selling price (“TPE”) and (iii) best estimate of selling price (“BESP”). The BESP reflects our best estimate of what the selling price would be if the deliverable was regularly sold by the Company on a stand-alone basis. In most cases the Company expects to use TPE or BESP for allocating consideration to each deliverable. The consideration allocated to each unit of accounting is recognized as the related goods or services are delivered, limited to the consideration that is not contingent upon future deliverables. Analyzing the arrangement to identify deliverables requires the use of judgment, and each deliverable may be an obligation to deliver services, a right or license to use an asset, or another performance obligation.

In June 2015, the Company entered into a License Agreement (the “SUL Agreement”) granting Seqirus UK Limited (“SUL”) and its affiliates worldwide rights, excluding Israel, Japan, Korea and Taiwan, to develop, manufacture and commercialize RAPIVAB. The SUL Agreement provides for various types of payments, including a non-refundable upfront fee, milestone payments, and future royalties. Analysis of the SUL Agreement identified three deliverables: (i) license rights, (ii) inventory and (iii) regulatory support to obtain Canadian and European Union (“EU”) marketing approvals. The Company received an upfront payment of $33,740 from SUL, of which $7,000 was determined to be contingent upon EU marketing approval and will be deferred until that time. Approximately $21,777 of the upfront payment was allocated to the license rights and recognized as revenue in the second quarter. Approximately $3,740 of the upfront payment was allocated to the pending sale of inventory and was recognized during the third quarter, when the inventory transfer was completed. Approximately $1,223 of the revenue from the SUL Agreement will be recognized over the expected period of involvement in these regulatory support activities.

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 reasonably assured at the inception of the agreement; and (ii) the fees are non-refundable. Any milestone payments received prior to satisfying these revenue recognition criteria are recorded as deferred revenue.

Under the terms of the SUL Agreement, the Company may receive up to $12,000 in additional payments related to the successful achievement of regulatory milestones, including marketing approval (i) by the FDA for a pediatric indication, (ii) by the EMA for an adult indication in the EU and (iii) by Health Products and Food Branch of Health Canada (“Health Canada”) for an adult indication in Canada. The Company evaluated each event based payment under the provisions of ASU 2010-17,

Milestone Method of Revenue Recognition

, and determined that each event based payment met the criteria to be considered substantive and represents a milestone under the milestone method of accounting. No event based payments were achieved during the periods presented.

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.

Product Sales

The Company recognizes revenue for sales of RAPIVAB when title and substantially all the risks and rewards of ownership have transferred to the customer, which generally occurs on the date of shipment from our specialty distributors, utilizing the Sell-Through revenue recognition methodology. Product sales are recognized when there is persuasive evidence that an arrangement exists, title has passed, the price is fixed and determinable, and collectability is reasonably assured. Product sales are recognized net of estimated allowances, discounts, sales returns, chargebacks and rebates. In the United States, and prior to the SUL Agreement, the Company sold RAPIVAB to specialty distributors, who in turn, sell to physician offices, hospitals and federal, state and commercial health care organizations. With the completion of the SUL worldwide license of RAPIVAB, SUL will be primarily responsible for sales of RAPIVAB, other than U.S. Government stockpiling sales, and the Company’s commercial sales will be minimal.

Sales deductions consist of statutory rebates to state Medicaid, Medicare and other government agencies and sales discounts (including trade discounts and distribution service fees). These deductions are recorded as reductions from revenue from RAPIVAB in the same period as the related sales with estimates of future utilization derived from historical experience adjusted to reflect known changes in the factors that impact such reserves.

The Company utilizes data from external sources to help it estimate gross-to-net sales adjustments as they relate to the recognition of revenue for RAPIVAB sold. Externally sourced data includes, but is not limited to, information obtained from specialty distributors with respect to their inventory levels and their sell-through to customers, as well as information from third-party suppliers of market research data to the pharmaceutical industry.

The Company accounts for these sales deductions in accordance with authoritative guidance on revenue recognition when consideration is given by a vendor to a customer.

The Company has categorized and described more fully the following significant sales deductions, all of which involve estimates and judgments, which the Company considers to be critical accounting estimates, and require it to use information from external sources.

Rebates and Chargebacks

Statutory rebates to state Medicaid agencies and Medicare are based on statutory discounts to RAPIVAB’s selling price. As it can take up to nine months or more for information to be received on actual usage of RAPIVAB in Medicaid and other governmental programs, the Company maintains reserves for amounts payable under these programs relating to RAPIVAB sales.

Chargebacks claimed by specialty distributors are based on the differentials between product acquisition prices paid by the specialty distributors and lower government contract pricing paid by eligible customers covered under federally qualified programs.

The amount of the reserve for rebates and chargebacks is based on multiple qualitative and quantitative factors, including the historical and projected utilization levels, historical payment experience, changes in statutory laws and interpretations as well as contractual terms, product pricing (both normal selling prices and statutory or negotiated prices), changes in prescription demand patterns and utilization of the Company’s product through public benefit plans, and the levels of RAPIVAB inventory in the distribution channel. The Company acquires prescription utilization data from third-party suppliers of market research data to the pharmaceutical industry. The Company updates its estimates and assumptions each period and records any necessary adjustments to its reserves. Settlements of rebates and chargebacks typically occur within nine months from point of sale. To the extent actual rebates and chargebacks differ from the Company’s estimates, additional reserves may be required or reserves may need to be reversed, either of which would impact current period product revenue.

Discounts and Sales Incentives

Discounts and other sales incentives primarily consist of Inventory Management Agreement (“IMA”) Fees. Per contractual agreements with the Company’s specialty distributors, the Company provides an IMA fee based on a percentage of their purchases of RAPIVAB. The IMA fee rates are set forth in individual contracts. The Company tracks sales to these distributors each period and accrues a liability relating to the unpaid portion of these fees by applying the contractual rates to such product sales.

Product Returns

The Company does not record a product return allowance as it does not offer the ability to return goods once a bonafide shipment has been accepted by a specialty distributor.

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

	2015		2014		2013
Product sales, net	$	6,291	$	33	$	—
Royalty revenue		2,386		3,025		2,562
Collaborative and other research and development revenues:
U.S. Department of Health and Human Services		16,337		9,366		13,585
Green Cross Corporation		132		—		—
Shionogi (Japan)		1,184		1,184		1,184
Seqirus UK Limited		21,927		—		—
Total collaborative and other research and development revenues		39,580		10,550		14,769
Total revenues	$	48,257	$	13,608	$	17,331

Advertising

The Company engages in very limited distribution and direct-response advertising when promoting RAPIVAB. Advertising and promotional costs are expensed as the costs are incurred. Advertising and product promotion expenses were $103 and $290 for the years ended December 31, 2015 and 2014, respectively.

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 our 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” has occurred.

Interest Expense and Deferred Financing Costs

Interest expense for the years ended December 31, 2015, 2014 and 2013 was $5,200, $4,998 and $4,778, respectively, and relates to the issuance of the PhaRMA Notes. Costs directly associated with the issuance of the PhaRMA Notes have been capitalized and are included in other non-current assets on the Consolidated Balance Sheets. These costs are being amortized to interest expense over the term of the PhaRMA Notes using the effective interest rate method. Amortization of deferred financing costs included in interest expense was $439 for each of the years ended December 31, 2015, 2014 and 2013.

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 Currency Hedge Agreement does not qualify for hedge accounting treatment; therefore mark to market adjustments are recognized in the Company’s Consolidated Statements of Comprehensive Loss. Cumulative mark to market adjustments for the years ended December 31, 2015, 2014 and 2013 resulted in a loss of $564 and gains of $5,487 and $5,294, respectively. Mark to market adjustments are 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, a realized currency exchange gain of $1,654 was recognized in 2015 related to the exercise of a U.S. dollar/Japanese yen currency option under our foreign currency hedge. The Company is also required to post collateral in connection with the mark to market adjustments based on defined thresholds. As of December 31, 2015 and December 31, 2014, no hedge collateral was posted under the agreement.

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, 2015, 2014, and 2013 does not include 3,524, 3,991 and 1,430 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 the Company to make estimates and assumptions that affect the amounts reported in the financial statements. Actual results could differ from those estimates.

Significant Customers and Other Risks

Significant Customers

Prior to the SUL Agreement, the Company relied primarily on three specialty distributors to purchase and supply the majority of RAPIVAB. These three pharmaceutical specialty distributors accounted for greater than 90% of all RAPIVAB product sales to date and accounted for predominantly all of the Company’s outstanding receivables from product sales. The loss of one or more of these specialty distributors as a customer could negatively impact the commercialization of RAPIVAB. However, the Company will utilize these specialty distributors on a limited basis subsequent to the SUL collaboration as SUL, and other peramivir collaboration partners, will be responsible for commercial sales on a worldwide basis. In addition, in connection with the SUL collaboration, all peramivir sales (i.e., RAPIVAB, RAPIACTA, and PERAMIFLU) will be made by the Company’s partners and the Company will be reliant on these partners to generate sales and remit cash to satisfy receivables.

The Company’s primary source of revenue that has an underlying cash flow stream is the reimbursement of RAPIVAB and BCX4430 development expenses earned under cost-plus-fixed-fee contracts with BARDA/HHS and NIAID/HHS, respectively. The Company relies on BARDA/HHS and NIAID/HHS to reimburse predominantly all of the development costs for its RAPIVAB and BCX4430 programs. Accordingly, reimbursement of these expenses represents a significant portion of the Company’s collaborative and other research and development revenues. The completion (as with the June 30, 2014 BARDA/HHS peramivir development contract) or termination of the NIAID/HHS and BARDA/HHS BCX4430 contracts could negatively impact the Company’s future Consolidated Statements of Comprehensive Loss and Cash Flows. In addition, the Company also recognizes royalty revenue from the net sales of RAPIACTA by Shionogi; however, the underlying cash flow from these royalty payments 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 RAPIVAB, as well as for its other product candidates in development. Delays in the manufacture or distribution of any product could adversely impact the commercial revenue and future procurement stockpiling of RAPIVAB.

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.

Note 2 - Furniture and Equipment

12 Months Ended

Dec. 31, 2015

Notes to Financial Statements

Property, Plant and Equipment Disclosure [Text Block]

Note 2 — Property and Equipment

Property and equipment consisted of the following at December 31:

	2015			2014
Furniture and fixtures	$	718		$	542
Office equipment		1,122			1,115
Software		1,427			1,423
Laboratory equipment		6,004			5,786
Leased equipment		63			63
Leasehold improvements		5,610			5,303
Construction in progress		2,821			—
Building		1,589			—
		19,354			14,232
Less accumulated depreciation and amortization		(14,205	)		(14,025	)
Property and equipment, net	$	5,149		$	207

Depreciation and amortization expense for the years ended December 31, 2015, 2014 and 2013 was $180, $177 and $304, respectively.

Note 3 - Royalty Monetization	12 Months Ended
Note 3 - Royalty Monetization	Dec. 31, 2015
Notes to Financial Statements
Royalty Monetization [Text Block]	Note 3— Royalty Monetization Overview On March 9, 2011, the Company completed a $30,000 financing transaction to monetize certain future royalty and milestone payments under the Shionogi Agreement, pursuant to which Shionogi licensed from the Company the rights to market RAPIACTA in Japan and, if approved for commercial sale, 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 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 will be paid by Shionogi in Japanese yen and milestone payments will 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 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 2013, Royalty Sub paid $1,844 of interest on the PhaRMA Notes from royalty payments received from RAPIACTA ® sales from the preceding four calendar quarters. This payment resulted in an obligation shortfall of approximately $2,356 associated with accrued interest due September 3, 2013. As stipulated under the PhaRMA Notes Indenture, if the amount available for payment on any Payment Date is insufficient to pay all of the interest due on a Payment Date, the shortfall in interest will accrue interest at the interest rate applicable to the PhaRMA Notes compounded annually. Accordingly, commencing in September 2013, the Company began accruing interest at 14% per annum on the interest shortfall of $2,356. In March, June and August of 2014, Royalty Sub paid additional interest of $446, $1,882 and $70, respectively, bringing the 2013 shortfall down to $222 as of September 30, 2014. 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. As a result of the event of default under the PhaRMA Notes, the holders of the PhaRMA Notes may pursue acceleration 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 acceleration or 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. In addition, the Company may incur costs associated with liquidating the related Currency Hedge Agreement, which would no longer be required in the event of foreclosure, or if the PhaRMA Notes cease to be outstanding. 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. As of December 31, 2015, the PhaRMA Notes remain in default. 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, 2015, the aggregate fair value of the PhaRMA Notes was estimated to be approximately 50% of its carrying value of $30,000. The estimated fair value of the PhaRMA Notes is classified as Level 2 in the fair value hierarchy as defined in U.S. GAAP. The PhaRMA Notes are redeemable at the option of Royalty Sub at any time at a redemption price equal to the outstanding principal balance of the PhaRMA Notes being redeemed plus accrued and unpaid interest through the redemption date on the PhaRMA Notes being redeemed. 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 has the right to purchase dollars and sell yen at a rate of 100 yen per dollar for which the Company may be required to pay a premium in each year from 2016 through 2020, provided the Currency Hedge Agreement remains in effect. A payment of $1,950 will be required if, on May 18 of the relevant year, the U.S. dollar is worth 100 yen or less as determined in accordance with the Currency Hedge Agreement. The Currency Hedge Agreement does not qualify for hedge accounting treatment; therefore mark to market adjustments are recognized in the Company’s Consolidated Statement of Comprehensive Loss. Cumulative mark to market adjustments in 2015, 2014 and 2013 resulted in a loss of $564 and gains of $5,487 and $5,294 respectively. In addition, a realized currency exchange gain of $1,654 was recognized in 2015 related to the exercise of a U.S. dollar/Japanese yen currency option under our foreign currency hedge. The Company is also required to post collateral in connection with the mark to market adjustments based on defined thresholds. As of December 31, 2015 and 2014, no collateral was posted under the Currency Hedge Agreement. The Company will not be required at any time to post collateral exceeding the maximum premium payments remaining payable under the Currency Hedge Agreement. As of December 31, 2015, the maximum amount of hedge collateral the Company may be required to post is $9,750.

Note 4 - Lease Obligations and Other Contingencies

12 Months Ended

Dec. 31, 2015

Notes to Financial Statements

Commitments and Contingencies Disclosure [Text Block]

Note 4 — Lease Obligations and Other Contingencies

The Company has the following minimum payments under operating lease obligations that existed at December 31, 2015:

2016	$	651
2017		871
2018		870
2019		820
2020		651
Thereafter		3,045
Total minimum payments	$	6,908

The obligations in the preceding table are primarily related to the Company’s leases for buildings in Birmingham, Alabama and Durham, North Carolina. The lease for the Company’s headquarters in Durham, North Carolina expires June 30, 2020. The lease for the existing facility in Birmingham, Alabama currently expires on June 30, 2016; however, in 2015, the Company leased an additional approximate 32,000 square feet in Birmingham to house its new research facility. The Company began construction on leasehold improvements for its new research facility in 2015 and this lease obligates the Company for $4,839 of lease payments into 2027. Rent expense for operating leases was $664, $633, and $526 in 2015, 2014, and 2013, respectively.

Lease Financing Obligation

Based on the terms of the lease agreement for the new research facility in Birmingham, Alabama, the Company had construction period risks during the construction period and the Company was deemed the owner of the building (for accounting purposes only) during the construction period. Accordingly, the Company recorded an asset of $1,589, representing the Company’s leased portion of the building and recorded a corresponding liability. Upon completion of leasehold improvement construction, the Company will not meet the sale-leaseback criteria for de-recognition of the building asset and liability. Therefore, the lease is accounted for as a financing obligation. The asset will be depreciated over the expected duration of the lease, and rental payments will be treated as principal and interest payments on the lease financing obligation liability. The underlying accounting for this transaction has no impact on cash flows associated with the underlying lease and or construction in process.

At December 31, 2015, the lease financing obligation balance was $2,375 and was recorded as a long term liability on the consolidated balance sheets. The remaining future minimum payments under the lease financing obligation are $4,839.

Note 5 - Stockholders' Equity	12 Months Ended
Note 5 - Stockholders' Equity	Dec. 31, 2015
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	Note 5 — Stockholders’ Equity Sales of Common Stock On March 3, 2015, the Company filed a $150,000 shelf registration statement on Form S-3 with the SEC. This shelf registration statement became effective upon filing and allows 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. The Company intends to file a post-effective amendment to this registration statement, which will allow for its use by the Company when declared effective by the SEC’s staff. On November 6, 2013, the Company filed a $125,000 shelf registration statement on Form S-3 with the SEC. This shelf registration statement was declared effective in November 2013 and allows us 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 June 3, 2014, the Company issued 11,500 shares of common stock for gross proceeds of $115,000 under this $125,000 shelf registration statement. Net proceeds were approximately $107,800 after deducting underwriting discounts and offering expenses. The Company has $10,000 remaining under this shelf registration statement In August 2013, the Company completed a public offering of 4,600 shares of its common stock at a price of $4.40 per share, which included the underwriters’ over-allotment allocation of an additional 600 shares. Net proceeds were approximately $18,500 after deducting underwriting discounts and offering expenses. Shares of common stock in this offering were sold under the $70,000 shelf registration statement declared effective in July 2011. In June 2011, the Company entered into an At Market Issuance Sales Agreement (the “ATM Agreement”) with McNicoll, Lewis & Vlak (“MLV”) pursuant to which the Company was able to sell $70,000 in shares of its common stock at current market prices under a Form S-3 registration statement with MLV acting as the sales agent. During 2012, the Company sold an aggregate of 4,516 shares of common stock at an average per share price of $4.08 pursuant to the ATM Agreement for net proceeds of $17,805. During 2013, the Company sold an aggregate of 2,883 shares of common stock at an average per share price of $1.85 pursuant to the Agreement for net proceeds of $5,218.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-Topic 210
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
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-Publisher FASB
-Name Accounting Standards Codification
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Reference 12: http://www.xbrl.org/2003/role/presentationRef
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
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+ Details

Note 6 - Stock-Based Compensation

12 Months Ended

Dec. 31, 2015

Notes to Financial Statements

Disclosure of Compensation Related Costs, Share-based Payments [Text Block]

Note 6 — Stock-Based Compensation

Stock Incentive Plan

As of December 31, 2015, the Company had two stock-based employee compensation plans, the Stock Incentive Plan (“Incentive Plan”) and the Employee Stock Purchase Plan (“ESPP”), both which were amended and restated in March 2014 and approved by the Company’s stockholders in May 2014. Stock-based compensation expense of $9,705 ($9,485 of expense related to the Incentive Plan, $220 of expense related to the ESPP) was recognized during 2015, while $10,177 ($9,963 of expense related to the Incentive Plan, $214 of expense related to the ESPP) was recognized during 2014, and $4,368 ($4,253 of expense related to the Incentive Plan, $115 of expense related to the ESPP) was recognized during 2013.

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,
	2015		2014		2013
Research and development	$	7,580	$	8,906	$	3,664
General and administrative		2,125		1,271		704
Total stock-based compensation expense	$	9,705	$	10,177	$	4,368

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 granted to employees generally vest 25% each year until fully vested after four years. In January 2013, the Company made retention grants of stock option awards and restricted stock units. These awards vest 50% each year until fully vested after two years. In August 2013 and December 2014, the Company issued 1,032 and 1,250 performance-based stock options, respectively. These awards vest upon successful completion of specific development milestones. As of December 31, 2015, 75% of the August 2013 grants have vested based upon achievement of three milestones: (1) successful completion of the OPuS-1 clinical trial, for which vesting occurred in the second quarter of 2014, (2) FDA approval of RAPIVAB for which vesting occurred in the fourth quarter of 2014, and (3) initiation of a Phase 1 clinical trial to evaluate the safety, pharmacokinetics and pharmacodynamics of orally-administered BCX7353 in healthy volunteers, for which vesting occurred in the second quarter of 2015. Thus, as of December 31, 2015, 25% of the August 2013 performance-based grants and 100% of the December 2014 performance-based grants remain unvested and no compensation expense has been recognized for these portions of the previously issued performance-based grants. Stock option awards granted to non-employee directors of the Company generally vest monthly over one year. All stock option awards have contractual terms of 5 to 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:

	Awards Available			Options Outstanding			Weighted Average Exercise Price
Balance at December 31, 2012		2,815			8,073		$	6.09
Restricted stock awards granted		(310	)		—			—
Restricted stock awards cancelled		53			—			—
Stock option awards granted		(3,277	)		3,277			3.05
Stock option awards exercised		—			(563	)		2.37
Stock option awards cancelled		1,801			(1,801	)		7.22
Balance at December 31, 2013		1,082			8,986			4.99
Plan amendment		3,750			—			—
Restricted stock awards granted		(593	)		—			—
Restricted stock awards cancelled		—			—			—
Stock option awards granted		(1,965	)		1,965			10.99
Stock option awards exercised		—			(1,258	)		4.78
Stock option awards cancelled		88			(88	)		8.83
Balance at December 31, 2014		2,362			9,605			6.21
Restricted stock awards granted		(163	)		—			—
Restricted stock awards cancelled		1			—			—
Stock option awards granted		(2,217	)		2,217			11.52
Stock option awards exercised		—			(1,118	)		4.36
Stock option awards cancelled		33			(33	)		9.87
Balance at December 31, 2015		16			10,671		$	7.50

For stock option awards granted under the Incentive Plan during 2015, 2014 and 2013, 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 2015, 2014 and 2013 was $7.72, $8.02, and $1.28, 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 explanations describe the assumptions used by the Company to value the stock option awards granted during 2015, 2014, and 2013. 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 volatility over the most recent period corresponding with the expected life. The Company has assumed no expected dividend yield, as dividends have never been paid to stockholders and will not be 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 under the Incentive Plan

	2015			2014			2013
Expected Life		5.5			5.5			4.7
Expected Volatility		81	%		87	%		84	%
Expected Dividend Yield		0.0	%		0.0	%		0.0	%
Risk-Free Interest Rate		1.6	%		1.6	%		0.7	%

The total intrinsic value of stock option awards exercised under the Incentive Plan was $10,117 during 2015, $8,522 during 2014, $738 and during 2013. 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.

The following table summarizes, at December 31, 2015, 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
Range				Number	Weighted Average Remaining Life		Weighted Average Exercise Price		Number		Weighted Average Exercise Price
$	0	to	3	1,826		6.4	$	1.51		1,322	$	1.55
	3	to	6	2,792		6.1		4.63		2,329		4.53
	6	to	9	1,153		4.5		7.10		1,070		7.13
	9	to	12	3,728		8.1		11.07		714		11.45
	12	to	15	1,077		6.4		12.44		374		12.65
	15	to	18	95		9.5		15.39		—		—
$	0	to	18	10,671		6.7	$	7.50		5,809	$	5.70

The weighted average remaining contractual life of stock option awards exercisable under the Incentive Plan at December 31, 2015 was 5.0 years.

The aggregate intrinsic value of stock option awards outstanding and exercisable under the Incentive Plan at December 31, 2015 was $28,511. 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 Incentive Plan 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 Incentive Plan was $4,492 during 2015, $2,844 during 2014, and $3,483 during 2013.

As of December 31, 2015, the number of stock option awards vested and expected to vest under the Incentive Plan is 9,633. The weighted average exercise price of these stock option awards is $7.51 and their weighted average remaining contractual life is 6.6 years.

The following table summarizes the changes in the number and weighted-average grant-date fair value of non-vested stock option awards during 2015:

	Non-Vested Stock Option Awards			Weighted Average Grant-Date Fair Value
Balance December 31, 2014		4,385		$	4.27
Stock option awards granted		2,217			7.72
Stock option awards vested		(1,711	)		2.63
Stock option awards forfeited		(28	)		6.39
Balance December 31, 2015		4,863		$	6.40

As of December 31, 2015, there was approximately $18,607 of total unrecognized compensation cost related to non-vested employee stock option awards and restricted stock units granted by the Company. That cost is expected to be recognized as follows: $7,023 in 2016, $6,010 in 2017, $3,891 in 2018, and $1,683 in 2019.

Employee Stock Purchase Plan

The Company has reserved a total of 1,475 shares of common stock to be purchased under the ESPP, of which 497 shares remain available for purchase at December 31, 2015. 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 41, 49 and 89 shares of common stock purchased under the ESPP in 2015, 2014, and 2013, respectively, at a weighted average price per share of $8.65, $6.29, and $1.39, respectively. Expense of $220, $214, and $115, related to the ESPP was recognized during 2015, 2014, and 2013, 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 2015, 2014, and 2013, were $4.93, $4.41, and $1.27, respectively.

Note 7 - Income Taxes

12 Months Ended

Dec. 31, 2015

Notes to Financial Statements

Income Tax Disclosure [Text Block]

Note 7 — 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 differences between the Company’s effective tax rate and the statutory tax rate in 2015, 2014, and 2013 are as follows:

	2015			2014			2013
Income tax benefit at federal statutory rate (35%)	$	(15,057	)	$	(15,816	)	$	(10,538	)
State and local income taxes net of federal tax benefit		(819	)		(1,286	)		(839	)
Permanent items		560			258			738
Rate change		1,012			22			1,892
Expiration of attribute carryforwards		330			373			242
Research and development tax credits		(10,454	)		(748	)		(1,206	)
Orphan drug credit		4,307			—			—
Other		(218	)		(115	)		1,144
Change in valuation allowance		20,339			17,312			8,567
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:

	2015			2014
Balance at January 1,	$	472		$	284
Additions to current period tax positions		2,616			176
Additions to prior period tax positions		—			12
Reductions to prior period tax provisions		(3	)		—
Balance at December 31,	$	3,085		$	472

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:

	2015			2014
Deferred tax assets:
Net federal and state operating losses	$	142,836		$	135,922
Research and development credits		48,551			38,096
Fixed assets		1,054			1,073
Deferred revenue		4,240			3,798
Stock-based compensation		8,605			7,086
Other		2,590			1,178
Total deferred tax assets		207,876			187,153
Deferred tax liabilities:
Foreign currency derivative		(2,668	)		(2,285	)
Total deferred tax liabilities		(2,668	)		(2,285	)

Valuation allowance		(205,208	)		(184,868	)
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 $20,339 in 2015, $17,312 in 2014, and $8,567 in 2013.

As of December 31, 2015, the Company had federal operating loss carryforwards of $386,219, state operating loss carryforwards of $373,454, and research and development and orphan drug credit carryforwards of $48,551, which will expire at various dates from 2016 through 2035. The federal losses begin to expire in 2018, the state losses begin to expire in 2016 and the research and development contracts begin to expire in 2018.

The Company’s federal and state operating loss carryforwards include $15,655 of excess tax benefits related to a deduction from the exercise of stock options. The tax benefit of these deductions has not been recognized in deferred tax assets. If utilized, the benefits from these deductions will be recorded as adjustments to additional paid-in capital.

Tax years 2012-2014 remain open to examination by the major taxing jurisdictions to which the Company is subject. Additionally, years prior to 2012 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 2015, 2014, and 2013.

Note 8 - Employee 401(k) Plan	12 Months Ended
Note 8 - Employee 401(k) Plan	Dec. 31, 2015
Notes to Financial Statements
Pension and Other Postretirement Benefits Disclosure [Text Block]	Note 8 — 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 $366, $361, and $313, in 2015, 2014, and 2013, respectively.

Note 9 - Collaborative and Other Research and Development Contracts	12 Months Ended
	Dec. 31, 2015
Notes to Financial Statements
Collaborative Arrangement Disclosure [Text Block]	Note 9 — Collaborative and Other Research and Development Contracts U.S. Department of Health and Human Services (“BARDA/HHS”). In January 2007, the U.S. Department of Health and Human Services (“BARDA/HHS”) awarded the Company a $102,661, four-year contract for the advanced development of peramivir for the treatment of influenza. During 2009, peramivir clinical development shifted to focus on intravenous delivery and the treatment of hospitalized patients. To support this focus, a September 2009 contract modification was awarded to extend the i.v. peramivir program and to increase funding by $77,191. On February 24, 2011, the Company announced that BARDA/HHS had awarded it a $55,000 contract modification, intended to fund completion of the Phase 3 development of i.v. peramivir for the treatment of patients hospitalized with influenza. That contract modification brought the total contract award from BARDA/HHS to $234,852 and provided funding to support the filing of a NDA to seek regulatory approval for i.v. peramivir in the U.S. In December 2013, BioCryst submitted an NDA filing for i.v. peramivir to the FDA and the NDA was approved in December 2014. The BARDA/HHS contract expired on June 30, 2014. On March 31, 2015, the Company announced that the Biomedical Research and Development Authority within the U.S. Department of Health and Human Services’ Office of the Assistant Secretary for Preparedness and Response awarded BioCryst a contract for the continued development of BCX4430 as a potential treatment for diseases caused by RNA pathogens, including filoviruses. This BARDA/HHS contract includes a base contract of $13,314 to support BCX4430 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 $36,169. As of September 30, 2015, a total of $16,300 has been awarded under exercised options within this contract. National Institute of Allergy and Infectious Diseases (“NIAID/HHS”). In September 2013, NIAID/HHS contracted with the Company for the development of BCX4430 as a treatment for Marburg virus disease. NIAID/HHS, part of the National Institutes of Health, made an initial award of $5,000 to the Company. The total funding under this contract as of December 31, 2015 could be up to $34,002, if all contract options are exercised by NIAID/HHS, over a five year period. The goals of this contract, including amendments, are to file IND applications for intravenous and intramuscular BCX4430 for the treatment of Marburg virus disease, to study BCX4430 as a treatment for Ebola virus disease and to conduct an initial Phase 1 human clinical trial. As of December 31, 2015, a total of $29,875 has been awarded under exercised options within this contract. BCX4430 is the lead compound in the Company’s BSAV research program. The contracts with BARDA/HHS and NIAID/HHS are cost-plus-fixed-fee contracts. That is, the Company is entitled to receive reimbursement for all costs incurred in accordance with the contracts provisions that are related to the development of peramivir and BCX4430 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. Seqirus UK Limited (“SUL”). On June 16, 2015, the Company and Seqirus UK Limited ("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"). RAPIVAB is an intravenous treatment for acute uncomplicated influenza and is currently licensed for use in the United States, Japan and Korea. RAPIVAB is the first and only intravenous influenza treatment in the world and was approved by the U.S. Food and Drug Administration in December 2014 for the treatment of acute uncomplicated influenza in patients 18 years and older who have been symptomatic for no more than two days. The Company retains all rights and associated economics to procure pandemic stockpiling orders for RAPIVAB from the U.S. Government, while SUL has the right to pursue government stockpiling outside the U.S. Pursuant to the SUL Agreement, RAPIVAB will be commercialized by CSL's subsidiary, SUL, which specializes in influenza prevention through the supply of seasonal and pandemic vaccine to global markets. SUL will manufacture, commercialize and exercise decision-making authority with respect to the development and commercialization of RAPIVAB within the Territory and be responsible for all related costs, including sales and promotion. In December 2013, the Company submitted a New Drug Application ("NDA") for RAPIVAB to the FDA. Under the terms of the SUL Agreement, the Company is responsible for fulfilling all post-marketing approval commitments in connection with the FDA's approval of the NDA, and upon fulfillment will transfer ownership of and financial responsibility for the NDA to SUL. Pursuant to potential rights to sell RAPIVAB in Canada and the EU, the Company is also responsible for regulatory filings and interactions with the Health Canada and the European Medicines Agency ("EMA") until marketing approval for RAPIVAB is obtained and assigned to SUL. In accordance with the SUL Agreement, the Company and SUL formed a joint steering committee, composed of an equal number of representatives from each party, to oversee, review and coordinate the conduct and progress of the commercialization of RAPIVAB in the Territory and any additional development. Under the terms of the SUL Agreement, the Company received an upfront payment of $33,740, and may receive up to $12,000 in additional milestone payments related to the successful achievement of regulatory milestones, including marketing approval (i) by the FDA for a pediatric indication, (ii) by the EMA for an adult indication in the EU and (iii) by Health Canada for an adult indication in Canada. The Company is also entitled under the SUL Agreement to receive tiered royalties at a percentage rate beginning in the mid-teens contingent upon meeting minimum thresholds of net sales, as well as a low-thirties percentage of the gross profit from government stockpiling purchases made outside the U.S. Specifically, the Company receives tiered royalties at a percentage rate in the mid-teens to low-forties on net sales in the U.S. during a Contract Year (defined as July 1 - June 30) and tiered royalties at a percentage rate in the mid-teens to mid-twenties on net sales in the Territory, other than in the U.S., during a Calendar Year, each subject to certain downward adjustments for circumstance or events impacting the overall market opportunity. SUL's royalty payment obligations commence on the date of the SUL Agreement and expire, on a country-by-country basis, upon the later of (i) the expiration of legal exclusivity in such country and (ii) ten years from the date of the SUL Agreement (the "Royalty Term"). The Company developed RAPIVAB under a license from UAB and will owe sublicense payments to them on any future milestone payments and/or royalties received by the Company from SUL. 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 them 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. Shionogi submitted an NDA to the Taiwan FDA in late 2013. 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 forodesine, a Purine Nucleoside Phosphorylase (“PNP”) inhibitor, for use in oncology (the “Original Agreement”). Under the terms of the Original Agreement, Mundipharma obtained rights to forodesine in markets across Europe, Asia, and Australasia in exchange for a $10,000 up-front payment. The Company deferred revenue recognition of the $10,000 up-front payment that was received from Mundipharma in February 2006 because the Company was involved in the continued development of forodesine. Amortization of this revenue commenced in February 2006 and was initially scheduled to end in October 2017, which is the date of expiration for the last-to-expire patent covered by the agreement. The Company also deferred revenue recognition of a $5,000 payment received from Mundipharma in connection with the initiation of a clinical trial in 2007. Amortization of this deferred revenue commenced in 2007 and was initially scheduled to end in October 2017. Under its agreement with AECOM/IRL, the Company paid sublicense payments related to these upfront cash payments received from Mundipharma. Expense recognition of these sublicense payments was deferred and recognized under the same term as the related deferred revenue. On November 11, 2011, the Company entered into the Amended and Restated License and Development Agreement (the “Amended and Restated Agreement”) with Mundipharma, amending and restating the Original Agreement. Under the terms of the Amended and Restated Agreement, Mundipharma obtained worldwide rights to forodesine. Commencing on November 11, 2011, Mundipharma controls the development and commercialization of forodesine and assumes all future development and commercialization costs. The Amended and Restated Agreement 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 forodesine is sold by Mundipharma. These royalties are subject to downward adjustments based on the then-existing patent coverage and/or the availability of generic compounds in each country. The Amended and Restated Agreement is a multiple element arrangement for accounting purposes, in which the Company is required to deliver to Mundipharma both the worldwide rights to forodesine in the field of oncology and the transfer of product data and know-how to permit Mundipharma to develop and commercialize forodesine (the “Knowledge Transfer”). The Company accounted for these elements as a combined unit of accounting as they do not have stand-alone value to Mundipharma. The worldwide license rights were granted to Mundipharma on November 11, 2011 and the Knowledge Transfer was completed during the first quarter of 2012. 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, (collectively, the “Licensors”). The lead product candidates from this collaboration are forodesine and ulodesine. 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. The Company agreed to use commercially reasonable efforts to develop these drugs. In addition, the Company has agreed 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 of these inhibitors, single digit royalties on net sales of any resulting product made by the Company, and to share approximately one quarter 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. This agreement may be terminated by the Company at any time by giving 60 days advance notice or in the event of material uncured breach by the Licensors. In May 2010, the Company amended the licensee agreement through which the Company obtained worldwide exclusive rights to develop and ultimately distribute any product candidates that might arise from research on a series of PNP inhibitors, including forodesine and ulodesine. Under the terms of the amendment, the Licensors agreed to accept a reduction of one-half in the percentage of future payments received from third-party sub licensees of the licensed PNP inhibitors that must be paid to the Licensors. This reduction does not apply to (i) any milestone payments the Company may receive in the future under its license agreement dated February 1, 2006 with Mundipharma and (ii) royalties received from its sub licensees in connection with the sale of licensed products, for which the original payment rate will remain in effect. The rate of royalty payments to the Licensors based on net sales of any resulting product made by the Company remains unchanged. In consideration for these modifications in 2010, the Company issued to the Licensors shares of its common stock with an aggregate value of $5,911 and paid the Licensors $90 in cash. Additionally, at the Company’s sole option and subject to certain agreed upon conditions, any future non-royalty payments due to be paid by it to the Licensors under the license agreement may be made either in cash, in shares of its common stock, or in a combination of cash and shares. On November 17, 2011, the Company further amended its agreements with the Licensors whereby the Licensors agreed to accept a reduction of one-half in the percentage of Net Proceeds (as defined) received by the Company under its Amended and Restated Agreement with Mundipharma that will be paid to AECOM/IRL. On June 19, 2012, the Company further amended its agreements with AECOM/IRL whereby the parties clarified the definition of the field with respect to PNP inhibition and AECOM/IRL agreed to exclusive worldwide license of BCX4430 to BioCryst for any antiviral use. At its sole option and subject to certain agreed upon conditions, any future non-royalty payments due to be paid by the Company to AECOM/IRL under the license agreement may be made either in cash, in shares of the Company’s common stock, or in a combination of cash and shares. On January 6, 2014, the Carbohydrate Chemistry Research Team from Callaghan Innovation Research Limited, formerly Industrial Research Limited, transferred to Victoria University of Wellington (“VUW”) to establish the Ferrier Research Institute. The intellectual property rights relating to this research team, and the contracts relating to that intellectual property were transferred to a wholly owned subsidiary of VUW, including the contracts to which BioCryst is a party. The parties executed novation agreements in order to effectuate the transfer. Except for a substitution of parties, the terms and conditions of the contracts are substantially the same 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 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 have initial 25-year terms, 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, Green Cross and SUL agreements, or commercializes products related to these programs, the Company will owe sublicense fees or royalties on amounts it receives.

Note 10 - Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2015

Notes to Financial Statements

Quarterly Financial Information [Text Block]

Note 10 — Quarterly Financial Information (Unaudited)

	First			Second			Third			Fourth
2015 Quarters
Revenues	$	6,826		$	25,842		$	10,987		$	4,602
Net (Loss) Income		(15,164	)		4,901			(14,621	)		(18,135	)
Basic net (loss) income per share		(0.21	)		0.07			(0.20	)		(0.25	)
Diluted net (loss) income per share		(0.21	)		0.06			(0.20	)		(0.25	)
2014 Quarters
Revenues	$	3,458		$	1,466		$	3,238		$	5,446
Net Loss		(10,137	)		(14,649	)		(8,731	)		(11,672	)
Basic and diluted net loss per share		(0.17	)		(0.23	)		(0.12	)		(0.16	)

Note 11 - Recent Accounting Pronouncements	12 Months Ended
Note 11 - Recent Accounting Pronouncements	Dec. 31, 2015
Notes to Financial Statements
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	Note 11 — Recent Accounting Pronouncements In November 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2015-17, Balance Sheet Classification of Deferred Taxes , requiring all deferred tax assets and liabilities, and any related valuation allowance, to be classified as noncurrent on the balance sheet. The classification change for all deferred taxes as noncurrent simplifies entities’ processes as it eliminates the need to separately identify the net current and net noncurrent deferred tax asset or liability in each jurisdiction and allocate valuation allowances. We elected to prospectively adopt the accounting standard in the beginning of our fourth quarter of fiscal 2015. Adoption of this standard had no impact on the Company’s consolidated financial statements. In April 2015, the FASB issued ASU No.2015-03, Simplifying the Presentation of Debt Issuance Costs . This standard amends existing guidance to require the presentation of debt issuance costs in the balance sheet as a deduction from the carrying amount of the related debt liability instead of a deferred charge. It is effective for annual reporting periods beginning after December 15, 2015. Early adoption is permitted. The Company does not expect this standard will have a material impact on its consolidated financial statements. In August 2014, the FASB issued ASU No. 2014-15 – Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern, which defines management’s responsibility to evaluate, at each annual and interim reporting period, whether there are conditions or events that raise substantial doubt about an entity’s ability to continue as a going concern within one year after the date the financial statements are issued and to provide related footnote disclosures in certain circumstances. In connection with each annual and interim period, management must assess if there is substantial doubt about the company’s ability to continue as a going concern within one year after the issuance date. Disclosures are required if conditions give rise to substantial doubt. This standard is effective for all companies in the first annual period ending after December 15, 2016, and interim periods thereafter, with early adoption permitted. The Company is currently evaluating the impact this standard will have on its financial statements and disclosures. In May 2014, the FASB issued ASU 2014-09 – Revenue from Contracts with Customers , which provides a single, comprehensive revenue recognition model for all contracts with customers. The core principal of this ASU is that an entity should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. In July 2015, the FASB finalized a one year delay in the effective date of this standard, which will now be effective January 1, 2018; however, early adoption is permitted any time after the original effective date, January 1, 2017. Companies can transition to the new standard under the full retrospective method or the modified retrospective method. The Company is currently evaluating the impact this standard will have on its consolidated financial statements.

- Definition

The entire disclosure of changes in accounting principles, including adoption of new accounting pronouncements, that describes the new methods, amount and effects on financial statement line items.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6507316

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Direct Effects of a Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6510796

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=56949863&loc=d3e22583-107794

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Indirect Effects of a Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6515603

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=56949863&loc=d3e22580-107794

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.10-01.(b)(6))
-URI http://asc.fasb.org/extlink&oid=27015980&loc=d3e46468-122699

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Accounting Change
-URI http://asc.fasb.org/extlink&oid=6503790

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=56949863&loc=d3e22499-107794

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Retrospective Application
-URI http://asc.fasb.org/extlink&oid=6523989

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=51655806&loc=d3e765-108305

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=51655806&loc=d3e725-108305

+ Details

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2015

Accounting Policies [Abstract]

Description of Company [Policy Text Block]

The Company

Consolidation, Policy [Policy Text Block]

Basis of Presentation

Reclassification, Policy [Policy Text Block]

Reclassifications

Long term deferred rent as of December 31, 2014 has been reclassified to conform to the 2015 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, 2015
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	26,557	$	88	$	—	$	(99	)	$	26,546
Corporate debt securities		21,820		184		—		(41	)		21,963
Certificates of deposit		21,884		21		5		(72	)		21,838
Total investments	$	70,261	$	293	$	5	$	(212	)	$	70,347

	December 31, 2014
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	20,307	$	22	$	—	$	(23	)	$	20,306
Corporate debt securities		27,152		151		5		(47	)		27,261
Commercial paper		11,838		6		—		(63	)		11,781
Total investments	$	59,297	$	179	$	5	$	(133	)	$	59,348

The following table summarizes the scheduled maturity for the Company’s investments at December 31, 2015 and 2014.

	2015		2014
Maturing in one year or less	$	22,664	$	18,232
Maturing after one year through two years		28,395		25,459
Maturing after two years		19,288		15,657
Total investments	$	70,347	$	59,348

Receivables, Policy [Policy Text Block]

Receivable from Collaborations

	December 31, 2015
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	—	$	5,536	$	5,536
Shionogi & Co. Ltd.		469		—		469
Seqirus UK Limited		210		28		238
Total receivables	$	679	$	5,564	$	6,243

	December 31, 2014
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	—	$	2,778	$	2,778
Shionogi & Co. Ltd.		1,071		—		1,071
Total receivables	$	1,071	$	2,778	$	3,849

Receivables from Product Sales

Inventory, Policy [Policy Text Block]

Inventory

During 2014, in connection with the FDA approval of RAPIVAB, the Company began capitalizing costs associated with the production of RAPIVAB inventories.

The Company’s inventory consisted of the following:

	As of December 31,
	2015		2014
Work in process	$	1,612	$	267
Finished goods		—		416
Net inventories	$	1,612	$	683

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 our raw materials, drug substance and drug products; and

•

professional fees.

Accrued expenses were comprised of the following:

	December 31,
	2015		2014
Compensation and benefits	$	424	$	2,105
Development costs		10,398		4,232
Inventory		549		397
Professional fees		242		238
Duties and taxes		102		75
Other		4,522		4,282
Total accrued expenses	$	16,237	$	11,329

As of December 31, 2015 and 2014, the carrying value of accrued expenses approximates their fair value due to their short-term settlement.

Income Tax, Policy [Policy Text Block]

Income Taxes

Comprehensive Income, Policy [Policy Text Block]

Accumulated Other Comprehensive Loss

Revenue Recognition, Policy [Policy Text Block]

Revenue Recognition

Collaborative and Other Research and Development Arrangements and Royalties

Milestone Method of Revenue Recognition

Product Sales

The Company accounts for these sales deductions in accordance with authoritative guidance on revenue recognition when consideration is given by a vendor to a customer.

Rebates and Chargebacks

Discounts and Sales Incentives

Product Returns

The Company does not record a product return allowance as it does not offer the ability to return goods once a bonafide shipment has been accepted by a specialty distributor.

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

	2015		2014		2013
Product sales, net	$	6,291	$	33	$	—
Royalty revenue		2,386		3,025		2,562
Collaborative and other research and development revenues:
U.S. Department of Health and Human Services		16,337		9,366		13,585
Green Cross Corporation		132		—		—
Shionogi (Japan)		1,184		1,184		1,184
Seqirus UK Limited		21,927		—		—
Total collaborative and other research and development revenues		39,580		10,550		14,769
Total revenues	$	48,257	$	13,608	$	17,331

Advertising

Research and Development Expense, Policy [Policy Text Block]

Research and Development Expenses

Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]

Stock-Based Compensation

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

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

12 Months Ended

Dec. 31, 2015

Notes Tables

Available-for-sale Securities [Table Text Block]

	December 31, 2015
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	26,557	$	88	$	—	$	(99	)	$	26,546
Corporate debt securities		21,820		184		—		(41	)		21,963
Certificates of deposit		21,884		21		5		(72	)		21,838
Total investments	$	70,261	$	293	$	5	$	(212	)	$	70,347

	December 31, 2014
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	20,307	$	22	$	—	$	(23	)	$	20,306
Corporate debt securities		27,152		151		5		(47	)		27,261
Commercial paper		11,838		6		—		(63	)		11,781
Total investments	$	59,297	$	179	$	5	$	(133	)	$	59,348

Available For Sale Securities Debt Maturities Fair Value [Table Text Block]

	2015		2014
Maturing in one year or less	$	22,664	$	18,232
Maturing after one year through two years		28,395		25,459
Maturing after two years		19,288		15,657
Total investments	$	70,347	$	59,348

Schedule of Receivables from Collaborations [Table Text Block]

	December 31, 2015
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	—	$	5,536	$	5,536
Shionogi & Co. Ltd.		469		—		469
Seqirus UK Limited		210		28		238
Total receivables	$	679	$	5,564	$	6,243

	December 31, 2014
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	—	$	2,778	$	2,778
Shionogi & Co. Ltd.		1,071		—		1,071
Total receivables	$	1,071	$	2,778	$	3,849

Schedule of Inventory, Current [Table Text Block]

	As of December 31,
	2015		2014
Work in process	$	1,612	$	267
Finished goods		—		416
Net inventories	$	1,612	$	683

Schedule of Accrued Liabilities [Table Text Block]

	December 31,
	2015		2014
Compensation and benefits	$	424	$	2,105
Development costs		10,398		4,232
Inventory		549		397
Professional fees		242		238
Duties and taxes		102		75
Other		4,522		4,282
Total accrued expenses	$	16,237	$	11,329

Schedule of Revenues from Collaborations [Table Text Block]

	2015		2014		2013
Product sales, net	$	6,291	$	33	$	—
Royalty revenue		2,386		3,025		2,562
Collaborative and other research and development revenues:
U.S. Department of Health and Human Services		16,337		9,366		13,585
Green Cross Corporation		132		—		—
Shionogi (Japan)		1,184		1,184		1,184
Seqirus UK Limited		21,927		—		—
Total collaborative and other research and development revenues		39,580		10,550		14,769
Total revenues	$	48,257	$	13,608	$	17,331

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

Note 2 - Furniture and Equipment (Tables)

12 Months Ended

Dec. 31, 2015

Notes Tables

Property, Plant and Equipment [Table Text Block]

	2015			2014
Furniture and fixtures	$	718		$	542
Office equipment		1,122			1,115
Software		1,427			1,423
Laboratory equipment		6,004			5,786
Leased equipment		63			63
Leasehold improvements		5,610			5,303
Construction in progress		2,821			—
Building		1,589			—
		19,354			14,232
Less accumulated depreciation and amortization		(14,205	)		(14,025	)
Property and equipment, net	$	5,149		$	207

Note 4 - Lease Obligations and Other Contingencies (Tables)

12 Months Ended

Dec. 31, 2015

Notes Tables

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

2016	$	651
2017		871
2018		870
2019		820
2020		651
Thereafter		3,045
Total minimum payments	$	6,908

Note 6 - Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Notes Tables

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Year Ended December 31,
	2015		2014		2013
Research and development	$	7,580	$	8,906	$	3,664
General and administrative		2,125		1,271		704
Total stock-based compensation expense	$	9,705	$	10,177	$	4,368

Schedule of Share-based Compensation, Activity [Table Text Block]

	Awards Available			Options Outstanding			Weighted Average Exercise Price
Balance at December 31, 2012		2,815			8,073		$	6.09
Restricted stock awards granted		(310	)		—			—
Restricted stock awards cancelled		53			—			—
Stock option awards granted		(3,277	)		3,277			3.05
Stock option awards exercised		—			(563	)		2.37
Stock option awards cancelled		1,801			(1,801	)		7.22
Balance at December 31, 2013		1,082			8,986			4.99
Plan amendment		3,750			—			—
Restricted stock awards granted		(593	)		—			—
Restricted stock awards cancelled		—			—			—
Stock option awards granted		(1,965	)		1,965			10.99
Stock option awards exercised		—			(1,258	)		4.78
Stock option awards cancelled		88			(88	)		8.83
Balance at December 31, 2014		2,362			9,605			6.21
Restricted stock awards granted		(163	)		—			—
Restricted stock awards cancelled		1			—			—
Stock option awards granted		(2,217	)		2,217			11.52
Stock option awards exercised		—			(1,118	)		4.36
Stock option awards cancelled		33			(33	)		9.87
Balance at December 31, 2015		16			10,671		$	7.50

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

	2015			2014			2013
Expected Life		5.5			5.5			4.7
Expected Volatility		81	%		87	%		84	%
Expected Dividend Yield		0.0	%		0.0	%		0.0	%
Risk-Free Interest Rate		1.6	%		1.6	%		0.7	%

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

				Outstanding					Exercisable
Range				Number	Weighted Average Remaining Life		Weighted Average Exercise Price		Number		Weighted Average Exercise Price
$	0	to	3	1,826		6.4	$	1.51		1,322	$	1.55
	3	to	6	2,792		6.1		4.63		2,329		4.53
	6	to	9	1,153		4.5		7.10		1,070		7.13
	9	to	12	3,728		8.1		11.07		714		11.45
	12	to	15	1,077		6.4		12.44		374		12.65
	15	to	18	95		9.5		15.39		—		—
$	0	to	18	10,671		6.7	$	7.50		5,809	$	5.70

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

	Non-Vested Stock Option Awards			Weighted Average Grant-Date Fair Value
Balance December 31, 2014		4,385		$	4.27
Stock option awards granted		2,217			7.72
Stock option awards vested		(1,711	)		2.63
Stock option awards forfeited		(28	)		6.39
Balance December 31, 2015		4,863		$	6.40

Note 7 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Notes Tables

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

	2015			2014			2013
Income tax benefit at federal statutory rate (35%)	$	(15,057	)	$	(15,816	)	$	(10,538	)
State and local income taxes net of federal tax benefit		(819	)		(1,286	)		(839	)
Permanent items		560			258			738
Rate change		1,012			22			1,892
Expiration of attribute carryforwards		330			373			242
Research and development tax credits		(10,454	)		(748	)		(1,206	)
Orphan drug credit		4,307			—			—
Other		(218	)		(115	)		1,144
Change in valuation allowance		20,339			17,312			8,567
Income tax expense	$	—		$	—		$	—

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

	2015			2014
Balance at January 1,	$	472		$	284
Additions to current period tax positions		2,616			176
Additions to prior period tax positions		—			12
Reductions to prior period tax provisions		(3	)		—
Balance at December 31,	$	3,085		$	472

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

	2015			2014
Deferred tax assets:
Net federal and state operating losses	$	142,836		$	135,922
Research and development credits		48,551			38,096
Fixed assets		1,054			1,073
Deferred revenue		4,240			3,798
Stock-based compensation		8,605			7,086
Other		2,590			1,178
Total deferred tax assets		207,876			187,153
Deferred tax liabilities:
Foreign currency derivative		(2,668	)		(2,285	)
Total deferred tax liabilities		(2,668	)		(2,285	)

Valuation allowance		(205,208	)		(184,868	)
Net deferred tax assets	$	—		$	—

Note 10 - Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2015

Notes Tables

Schedule of Quarterly Financial Information [Table Text Block]

	First			Second			Third			Fourth
2015 Quarters
Revenues	$	6,826		$	25,842		$	10,987		$	4,602
Net (Loss) Income		(15,164	)		4,901			(14,621	)		(18,135	)
Basic net (loss) income per share		(0.21	)		0.07			(0.20	)		(0.25	)
Diluted net (loss) income per share		(0.21	)		0.06			(0.20	)		(0.25	)
2014 Quarters
Revenues	$	3,458		$	1,466		$	3,238		$	5,446
Net Loss		(10,137	)		(14,649	)		(8,731	)		(11,672	)
Basic and diluted net loss per share		(0.17	)		(0.23	)		(0.12	)		(0.16	)

Note 1 - Significant Accounting Policies and Concentrations of Risk (Details Textual) - USD ($) shares in Thousands		1 Months Ended	12 Months Ended
	Nov. 06, 2013	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 09, 2011
Currency Hedge Agreement [Member]
Collateral Already Posted, Aggregate Fair Value			$ 0	$ 0
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivative, Loss on Derivative			564,000
Derivative, Gain on Derivative			$ 1,654,000	5,487,000	$ 5,294,000
JPR Royalty Sub LLC [Member]
Revenue Recognition Royalty and Milestone Revenue Recognized						$ 30,000,000
Maximum [Member]
Maturity of Investments			3 years
Maturity Period of High Quality Marketable Securities			3 years
Average Maturity Period of High Quality Marketable Securities			1 year 180 days
Maturity Period of Short Term Investment			1 year
Average Maturity for Portfolio Investments			1 year 180 days
Minimum [Member]
Maturity Period of Short Term Investment			90 days
Long-term Investment Maturity, Minimum			1 year
Certificates of Deposit [Member]
Restricted Cash and Cash Equivalents, Current			$ 150,000
Royalty Receivable [Member]
Restricted Cash and Cash Equivalents, Current			59,000
Collateral for Credit [Member]
Restricted Cash and Cash Equivalents			$ 1,403,000
Computer Equipment [Member]
Property, Plant and Equipment, Useful Life			3 years
Laboratory Equipment, Office Equipment and Software [Member]
Property, Plant and Equipment, Useful Life			5 years
Furniture and Fixtures [Member]
Property, Plant and Equipment, Useful Life			7 years
Building [Member]
Property, Plant and Equipment, Useful Life			10 years
Agreement [Member] \| CSL [Member] \| RAPIVABMember \| Contingent upon EU Marketing Approval [Member]
Proceeds from License Fees Received		$ 7,000,000
Agreement [Member] \| CSL [Member] \| RAPIVABMember \| Revenue from Sale of Inventory to be Recognized When the Inventory Transfer Is Complete [Member]
Deferred Revenue, Additions		3,740,000
Agreement [Member] \| CSL [Member] \| RAPIVABMember \| Regulatory Support Revenue for Canadian and EU Marketing Approvals, Portion Recognized Ratably Over Expected Period of Involvement [Member]
Deferred Revenue, Additions		1,223,000
Agreement [Member] \| CSL [Member] \| RAPIVABMember
Proceeds from License Fees Received		33,740,000
Revenues		21,777,000
Milestone Payment Maximum		$ 12,000,000
RAPIVABMember \| Customer Concentration Risk [Member] \| Sales Revenue, Product Line [Member]
Concentration Risk, Percentage			90.00%
PhaRMA Notes Member]
Interest Expense			$ 5,200,000	4,998,000	4,778,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax			13,000	0
Amortization of Financing Costs			439,000	439,000	439,000
Investments and Cash			100,858,000
Securities Offered	$ 10,000,000
Restricted Cash and Cash Equivalents, Current			1,612,000	150,000
Revenues			48,257,000	13,608,000	17,331,000
Advertising Expense			103,000	290,000
Interest Expense			$ 5,200,000	$ 4,998,000	$ 4,778,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			3,524	3,991	1,430

Note 1 - Fair Value of the Company's Investments by Type (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
US Government Agencies Debt Securities [Member]
Amortized Cost	$ 26,557	$ 20,307
Accrued Interest	88	22
Gross Unrealized Gains
Gross Unrealized Losses	(99)	(23)
Estimated Fair Value	26,546	20,306
Corporate Debt Securities [Member]
Amortized Cost	21,820	27,152
Accrued Interest	184	151
Gross Unrealized Gains		5
Gross Unrealized Losses	(41)	(47)
Estimated Fair Value	21,963	27,261
Certificates of Deposit [Member]
Amortized Cost	21,884
Accrued Interest	21
Gross Unrealized Gains	5
Gross Unrealized Losses	(72)
Estimated Fair Value	21,838
Commercial Paper [Member]
Amortized Cost		11,838
Accrued Interest		6
Gross Unrealized Gains
Gross Unrealized Losses		(63)
Estimated Fair Value		11,781
Amortized Cost	70,261	59,297
Accrued Interest	293	179
Gross Unrealized Gains	5	5
Gross Unrealized Losses	(212)	(133)
Estimated Fair Value	$ 70,347	$ 59,348

Note 1 - Scheduled Maturity for the Company's Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Maturing in one year or less	$ 22,664	$ 18,232
Maturing after one year through two years	28,395	25,459
Maturing after two years	19,288	15,657
Total investments	$ 70,347	$ 59,348

Note 1 - Summary of Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
US Department of Health and Human Services [Member] \| Billed Revenues [Member]
Receivables
US Department of Health and Human Services [Member] \| Unbilled Revenues [Member]
Receivables	5,536	2,778
US Department of Health and Human Services [Member]
Receivables	5,536	2,778
Shionogi and Co. Ltd [Member] \| Billed Revenues [Member]
Receivables	469	1,071
Shionogi and Co. Ltd [Member] \| Unbilled Revenues [Member]
Receivables
Shionogi and Co. Ltd [Member]
Receivables	469	1,071
CSL Limited [Member \| Billed Revenues [Member]
Receivables	210
CSL Limited [Member \| Unbilled Revenues [Member]
Receivables	28
CSL Limited [Member
Receivables	238
Billed Revenues [Member]
Receivables	679	1,071
Unbilled Revenues [Member]
Receivables	5,564	2,778
Receivables	$ 6,243	$ 3,849

Note 1 - Inventory (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Work in process	$ 1,612,000	$ 267,000
Finished goods		416,000
Net inventories	$ 1,612,000	$ 683,000

Note 1 - Accrued Expenses (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Development Cost [Member]
Development costs	$ 10,398,000	$ 4,232,000
Compensation and benefits	424,000	2,105,000
Inventory	549,000	397,000
Professional fees	242,000	238,000
Duties and taxes	102,000	75,000
Other	4,522,000	4,282,000
Total accrued expenses	$ 16,237,000	$ 11,329,000

Note 1 - Summary of Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
US Department of Health and Human Services [Member]
Collaborative and other research and development revenues:
Collaborative and other research and development revenues	$ 16,337	$ 9,366	$ 13,585
Green Cross Corporation [Member]
Collaborative and other research and development revenues:
Collaborative and other research and development revenues	132
Shionogi and Co. Ltd [Member]
Collaborative and other research and development revenues:
Collaborative and other research and development revenues	1,184	1,184	1,184
CSL [Member]
Collaborative and other research and development revenues:
Collaborative and other research and development revenues	21,927
Product sales, net	6,291	33
Royalty revenue	2,386	3,025	2,562
Collaborative and other research and development revenues	39,580	10,550	14,769
Revenues	$ 48,257	$ 13,608	$ 17,331

Note 2 - Furniture and Equipment (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Depreciation, Depletion and Amortization	$ 180	$ 177	$ 304

Note 2 - Furniture and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Furniture and Fixtures [Member]
Property, Plant and Equipment, Gross	$ 718	$ 542
Office Equipment [Member]
Property, Plant and Equipment, Gross	1,122	1,115
Software Development [Member]
Property, Plant and Equipment, Gross	1,427	1,423
Laboratory Equipment [Member]
Property, Plant and Equipment, Gross	6,004	5,786
Leased Equipment [Member]
Property, Plant and Equipment, Gross	63	63
Leasehold Improvements [Member]
Property, Plant and Equipment, Gross	5,610	5,303
Construction in Progress [Member]
Property, Plant and Equipment, Gross	2,821
Building [Member]
Property, Plant and Equipment, Gross	1,589
Property, Plant and Equipment, Gross	19,354	14,232
Less accumulated depreciation and amortization	(14,205)	(14,025)
Property and equipment, net	$ 5,149	$ 207

Note 3 - Royalty Monetization (Details Textual)		1 Months Ended				9 Months Ended	12 Months Ended
Note 3 - Royalty Monetization (Details Textual)	Mar. 09, 2011 USD ($)	Aug. 31, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2014 JPY (¥)	Sep. 30, 2014 USD ($)	Sep. 03, 2013 USD ($)
PhaRMA Notes Member] \| JPR Royalty Sub LLC [Member] \| Currency Hedge Agreement [Member]
Collateral Already Posted, Aggregate Fair Value							$ 0	$ 0
Maximum Amount of Collateral Required to Post							$ 9,750,000
PhaRMA Notes Member] \| JPR Royalty Sub LLC [Member] \| Shortfall 2013 [Member]
Interest Payable											$ 222,000
PhaRMA Notes Member] \| JPR Royalty Sub LLC [Member] \| Fair Value, Inputs, Level 2 [Member]
Notes Payable, Fair Value Disclosure									$ 30,000,000
PhaRMA Notes Member] \| JPR Royalty Sub LLC [Member]
Private Placement of Senior Secured Notes	$ 30,000,000
Debt Instrument, Interest Rate, Stated Percentage	14.00%				14.00%
Interest Paid		$ 70,000	$ 1,882,000	$ 446,000	$ 1,844,000
Interest Payable												$ 2,356,000
PhaRMA Notes Member] \| Currency Hedge Agreement [Member] \| Japan, Yen [Member]
Derivative, Forward Exchange Rate						100
PhaRMA Notes Member] \| Currency Hedge Agreement [Member]
Payments for (Proceeds from) Hedge, Investing Activities						$ 1,950,000
Required Foreign Currency Hedge Per Dollar \| ¥										¥ 100
PhaRMA Notes Member] \| JPR Royalty Sub LLC [Member]
Percentage of Carrying Amount in Excess of Fair Value							50.00%
JPR Royalty Sub LLC [Member] \| Royalty Monetization [Member]
Revenue Recognition Royalty and Milestone Revenue Recognized	$ 30,000,000
Revenue Recognition Royalty And Milestone Revenue Recognized, Net	22,691,000
Transaction Costs	4,309,000
Interest Reserve	3,000,000
Currency Hedge Agreement [Member]
Collateral Already Posted, Aggregate Fair Value							$ 0	0
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivative, Loss on Derivative							564,000
Derivative, Gain on Derivative							$ 1,654,000	$ 5,487,000	$ 5,294,000
JPR Royalty Sub LLC [Member]
Revenue Recognition Royalty and Milestone Revenue Recognized	$ 30,000,000

Note 4 - Lease Obligations and Other Contingencies (Details Textual)	12 Months Ended
	Dec. 31, 2015 USD ($) ft²	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Birmingham Research Facility [Member] \| Leasehold Improvements [Member]
Property, Plant and Equipment, Gross	$ 1,589,000
Birmingham Research Facility [Member] \| Long Term Liabilities [Member]
Lease Financing Obligation, Net of Current	2,375,000
Birmingham Research Facility [Member]
Operating Leases, Future Minimum Payments Due	4,839,000
Leasehold Improvements [Member]
Property, Plant and Equipment, Gross	$ 5,610,000	$ 5,303,000
Area of Real Estate Property \| ft²	32,000
Operating Leases, Future Minimum Payments Due		6,908,000
Operating Leases, Rent Expense, Net	$ 664,000	633,000	$ 526,000
Property, Plant and Equipment, Gross	19,354,000	14,232,000
Lease Financing Obligation, Net of Current	$ 2,375

Note 4 - Minimum Payments under Operating Lease Obligations (Details) $ in Thousands	Dec. 31, 2014 USD ($)
2016	$ 651
2017	871
2018	870
2019	820
2020	651
Thereafter	3,045
Total minimum payments	$ 6,908

Note 5 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, shares in Thousands		1 Months Ended	12 Months Ended
	Jun. 03, 2014	Aug. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 03, 2015	Jun. 30, 2014	Nov. 06, 2013	Jul. 13, 2011
Maximum Aggregate Offering Price							$ 150,000,000		$ 125,000,000
Issuance of common stock, shares (in shares)	11,500	4,600			2,883	4,516
Proceeds from Issuance of Common Stock	$ 115,000,000	$ 18,500,000		$ 106,600,000	$ 23,633,000	$ 17,805,000
Proceeds from Issuance or Sale of Equity	$ 107,800,000
Remaining Aggregate Offering Price									$ 10,000,000
Share Price		$ 4.40			$ 1.85	$ 4.08
Stock Issued During Period Shares for over Allotment Option Exercised by Underwriter		600
Common Stock to be Issued, Value								$ 70,000,000
Common Stock, Value, Issued			$ 734,000	$ 720,000						$ 70,000,000
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options					$ 5,218,000

Note 6 - Stock-Based Compensation (Details Textual) $ / shares in Units, shares in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2013 shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares	Dec. 31, 2012 shares
Incentive Plan [Member] \| Employee Stock 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		4 years
Incentive Plan [Member] \| Employee Stock Option [Member] \| Non-employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award, First Vesting Period After Grant Date		1 year
Incentive Plan [Member] \| Employee Stock Option [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		5 years
Incentive Plan [Member] \| Employee Stock Option [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		10 years
Incentive Plan [Member] \| Stock Options and Restricted Stock [Member] \| Vest 50% Each Year Until Fully Vested [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		50.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		2 years
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		75.00%
Number of Milestones Achieved		3
Share-based Compensation Arrangement by Shar-based Payment Award, Awards Unvested, Percentage		25.00%
Incentive Plan [Member] \| Performance Shares [Member] \| Vest Upon Successful Completion of Specific Development Milestones [Member] \| December 2014 [Member]
Share-based Compensation Arrangement by Shar-based Payment Award, Awards Unvested, Percentage		100.00%
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 \| shares	1,032	1,250
Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		$ 0
Allocated Share-based Compensation Expense		$ 9,485,000	$ 9,963,000	$ 4,253,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term		5 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares		$ 7.72	$ 8.02	$ 1.28
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value		$ 10,117,000	$ 8,522,000	$ 738,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value		28,511,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value		$ 4,492,000	2,844,000	3,483,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number \| shares		9,633
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price \| $ / shares		$ 7.51
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term		6 years 219 days
Employee Stock Purchase Plan [Member]
Allocated Share-based Compensation Expense		$ 220,000	$ 214,000	$ 115,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized \| shares		1,475
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant \| shares		497
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 \| shares		3
Shar-based Compensation Arrangement by Shar-based Payment Award, Maximum Number of Shares Per Employee, Amount		$ 25,000
Employee stock purchase plan sales, shares (in shares) \| shares		41	49	89
Employee Stock Ownership Plan (ESOP), Weighted Average Purchase Price of Shares Purchased \| $ / shares		$ 8.65	$ 6.29	$ 1.39
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares		$ 4.93	$ 4.41	$ 1.27
Number of Stock-based Compensation Plans		2
Allocated Share-based Compensation Expense		$ 9,705,000	$ 10,177,000	$ 4,368,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross \| shares		2,217
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares		$ 7.72
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized		$ 18,607,000
Employee Service Share-based Compensation Nonvested Awards Compensation Cost Expected to be Recognized For Remainder of Fiscal Year		7,023,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Expected to be Recognized Year Two		6,010,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Expected to be Recognized Year Three		3,891,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Expected to be Recognized Year Four		$ 1,683,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant \| shares		16	2,362	1,082	2,815

Note 6 - Stock-based Compensation Allocation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Research and Development Expense [Member]
Allocated Share-based Compensation Expense	$ 7,580,000	$ 8,906,000	$ 3,664,000
General and Administrative Expense [Member]
Allocated Share-based Compensation Expense	2,125,000	1,271,000	704,000
Allocated Share-based Compensation Expense	$ 9,705,000	$ 10,177,000	$ 4,368,000

Note 6 - Stock Incentive Plan Activities (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Awards Available (in shares)	2,362	1,082	2,815
Options Outstanding (in shares)	9,605	8,986	8,073
Weighted Average Exercise Price (in dollars per share)			$ 6.09
Restricted stock awards granted (in shares)	(163)	(593)	(310)
Restricted stock awards cancelled (in shares)	1		53
Stock option awards granted (in shares)	(2,217)	(1,965)	(3,277)
Stock option awards granted (in shares)	2,217	1,965	3,277
Stock option awards granted (in dollars per share)	$ 11.52	$ 10.99	$ 3.05
Stock option awards exercised (in shares)	(1,118)	(1,258)	(563)
Stock option awards exercised (in dollars per share)	$ 4.36	$ 4.78	$ 2.37
Stock option awards cancelled (in shares)	33	88	1,801
Stock option awards cancelled (in shares)	(33)	(88)	(1,801)
Stock option awards cancelled (in dollars per share)	$ 9.87	$ 8.83	$ 7.22
Awards Available (in shares)	16	2,362	1,082
Options Outstanding (in shares)	10,671	9,605	8,986
Weighted Average Exercise Price (in dollars per share)	$ 7.50	$ 6.21	$ 4.99
Plan amendment (in shares)		3,750

Note 6 - Weighted Average Assumptions for Stock Option Awards Granted to Employees and Directors under the Incentive Plan (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Expected Life	5 years 182 days	5 years 182 days	4 years 255 days
Expected Volatility	81.00%	87.00%	84.00%
Expected Dividend Yield	0.00%	0.00%	0.00%
Risk-Free Interest Rate	1.60%	1.60%	0.70%

Note 6 - Number of Stock Option Awards Exercisable and their Weighted Average Exercise Price (Details)	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Exercise Price Range 01 [Member]
Upper Exercise Price Range (in dollars per share) \| $ / shares	$ 1,826
Outstanding Number (in shares) \| shares	6,400
Outstanding Weighted Average Remaining Life	1 year 186 days
Outstanding Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 1,322
Exercisable Number (in shares) \| shares	1,550
Exercise Price Range 02 [Member]
Upper Exercise Price Range (in dollars per share) \| $ / shares	$ 2,792
Outstanding Number (in shares) \| shares	6,100
Outstanding Weighted Average Remaining Life	4 years 229 days
Outstanding Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 2,329
Exercisable Number (in shares) \| shares	4,530
Exercise Price Range 03 [Member]
Upper Exercise Price Range (in dollars per share) \| $ / shares	$ 1,153
Outstanding Number (in shares) \| shares	4,500
Outstanding Weighted Average Remaining Life	7 years 36 days
Outstanding Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 1,070
Exercisable Number (in shares) \| shares	7,130
Exercise Price Range 04 [Member]
Upper Exercise Price Range (in dollars per share) \| $ / shares	$ 3,728
Outstanding Number (in shares) \| shares	8,100
Outstanding Weighted Average Remaining Life	11 years 25 days
Outstanding Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 714
Exercisable Number (in shares) \| shares	11,450
Exercise Price Range 05 [Member]
Upper Exercise Price Range (in dollars per share) \| $ / shares	$ 1,077
Outstanding Number (in shares) \| shares	6,400
Outstanding Weighted Average Remaining Life	12 years 160 days
Outstanding Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 374
Exercisable Number (in shares) \| shares	12,650
Exercise Price Range 06 [Member]
Upper Exercise Price Range (in dollars per share) \| $ / shares	$ 95
Outstanding Number (in shares) \| shares	9,500
Outstanding Weighted Average Remaining Life	15 years 142 days
Outstanding Weighted Average Exercise Price (in dollars per share) \| $ / shares
Exercisable Number (in shares) \| shares
Upper Exercise Price Range (in dollars per share) \| $ / shares	$ 10,671
Outstanding Number (in shares) \| shares	6,700
Outstanding Weighted Average Remaining Life	7 years 182 days
Outstanding Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 5,809
Exercisable Number (in shares) \| shares	5,700

Note 6 - Changes in the Number and Weighted-Average Grant-Date Fair Value (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Non-vested stock option awards (in shares) \| shares	4,385
Weighted average grant-date fair value (in dollars per share) \| $ / shares	$ 4.27
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross \| shares	2,217
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares	$ 7.72
Stock option awards vested (in shares) \| shares	(1,711)
Stock option awards vested (in dollars per share) \| $ / shares	$ 2.63
Stock option awards forfeited (in shares) \| shares	(28)
Stock option awards forfeited (in dollars per share) \| $ / shares	$ 6.39
Non-vested stock option awards (in shares) \| shares	4,863
Weighted average grant-date fair value (in dollars per share) \| $ / shares	$ 6.40

Note 7 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
Note 7 - Income Taxes (Details Textual) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Domestic Tax Authority [Member]
Operating Loss Carryforwards	$ 386,219,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	373,454,000
Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	48,551,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	0	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	20,339,000	$ 17,312,000	$ 8,567,000
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options	$ 15,655,000

Note 7 - Differences Between the Company's Effective Tax Rate and the Statutory Tax Rate (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income tax benefit at federal statutory rate (35%)	$ (15,057,000)	$ (15,816,000)	$ (10,538,000)
State and local income taxes net of federal tax benefit	(819,000)	(1,286,000)	(839,000)
Permanent items	560,000	258,000	738,000
Rate change	1,012,000	22,000	1,892,000
Expiration of attribute carryforwards	330,000	373,000	242,000
Research and development tax credits	(10,454,000)	(748,000)	(1,206,000)
Orphan drug credit	4,307,000
Other	(218,000)	(115,000)	1,144,000
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	20,339,000	17,312,000	8,567,000
Income tax expense

Note 7 - Differences Between the Company's Effective Tax Rate and the Statutory Tax Rate (Details) (Parentheticals)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income tax benefit at federal statutory rate	35.00%	35.00%	35.00%

Note 7 - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Balance at	$ 472	$ 284
Additions to current period tax positions	2,616	176
Additions to prior period tax positions		12
Balance at	$ 3,085	$ 472

Note 7 - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Net federal and state operating losses	$ 142,836	$ 135,922
Research and development credits	48,551	38,096
Fixed assets	1,054	1,073
Deferred revenue	4,240	3,798
Stock-based compensation	8,605	7,086
Other	2,590	1,178
Total deferred tax assets	207,876	187,153
Foreign currency derivative	(2,668)	(2,285)
Total deferred tax liabilities	(2,668)	(2,285)
Valuation allowance	(205,208)	(184,868)
Net deferred tax assets

Note 8 - Employee 401(k) Plan (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 366	$ 361	$ 313

Note 9 - Collaborative and Other Research and Development Contracts (Details Textual) - USD ($) $ in Thousands		1 Months Ended							9 Months Ended	12 Months Ended	50 Months Ended
	Jun. 16, 2015	Sep. 30, 2013	Feb. 24, 2011	May 31, 2010	Sep. 30, 2009	Jan. 31, 2007	Jun. 30, 2006	Feb. 28, 2006	Sep. 30, 2015	Dec. 31, 2015	Feb. 24, 2011	Mar. 31, 2015	Nov. 11, 2011	Dec. 31, 2007
US Department of Health and Human Services [Member]
Collaborative Agreement Contract Value						$ 102,661
Collaborative Agreement Additional Contract Value			$ 55,000		$ 77,191
Collaborative Agreement Adjusted Contract Value											$ 234,852
National Institute of Allergy and Infectious Diseases [Member]
Proceeds from awards for Research and Development Contracts		$ 5,000
Expected Receivable From Awards for Research and Development Contracts										$ 34,002
Collaborative Agreement Period of Contract										5 years
Collaboration Agreement Additional Payments Received										$ 29,875
UAB [Member]
Period of Agreement										25 years
Renewable Period of Agreement										5 years
Base Contract [Member]
Government Contract Receivable												$ 13,314
Additional Development Options [Member]
Government Contract Receivable												22,855
ASPRBARDA Contract [Member]
Government Contract Receivable												$ 36,169
Proceeds from awards for Research and Development Contracts									$ 16,300
Green Cross Corporation [Member]
Proceeds from License Fees Received							$ 250
Mundipharma [Member] \| Upfront Payment [Member]
Deferred Revenue								$ 10,000
Mundipharma [Member] \| Clinical Trial 2007 [Member]
Deferred Revenue														$ 5,000
Mundipharma [Member]
Upfront Payments Receivable Amount								$ 10,000
Potential Milestone Payments Receivable													$ 15,000
AECOM and IRL [Member]
Milestone Payment Maximum										$ 4,000
Milestone Payment Minimum										1,400
Annual License Fee Minimum										150
Annual License Fee Maximum										$ 500
Advance Notice Period for Termination of Agreement										60 days
Stock Issued During Period, Value, for Modification of License Agreement				$ 5,911
Payments for Modification of License Agreement				$ 90
CSL Limited [Member
Proceeds from License Fees Received	$ 33,740
Milestone Payment Maximum	$ 12,000
Royalty Term	10 years

Note 10 - Quarterly Financial Information (Unaudited) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Revenues	$ 4,602	$ 10,987	$ 25,842	$ 6,826
Net loss	$ (18,135)	$ (14,621)	$ 4,901	$ (15,164)
Basic net (loss) income per share (in dollars per share)	$ (0.25)	$ (0.20)	$ 0.07	$ (0.21)
Diluted net (loss) income per share (in dollars per share)	$ (0.25)	$ (0.20)	$ 0.06	$ (0.21)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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