BioCryst Pharmaceuticals (BCRX) 10-K 1 Mar 21 2020 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Jan. 31, 2021	Jun. 30, 2020
Document Information [Line Items]
Entity Central Index Key	0000882796
Entity Registrant Name	BIOCRYST PHARMACEUTICALS INC
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	000-23186
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	62-1413174
Entity Address, Address Line One	4505 Emperor Blvd., Suite 200
Entity Address, City or Town	Durham
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27703
City Area Code	919
Local Phone Number	859-1302
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	BCRX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 832,869,919
Entity Common Stock, Shares Outstanding		177,182,751

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
ASSETS
Cash and cash equivalents	$ 272,127	$ 114,172
Restricted cash	2,221	1,551
Investments	28,239	22,054
Receivables	8,646	22,146
Inventory	7,039	0
Prepaid expenses and other current assets	5,528	4,422
Total current assets	323,800	164,345
Property and equipment, net	7,113	7,347
Other assets	3,802	3,590
Total assets	334,715	175,282
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accounts payable	18,713	13,988
Accrued expenses	33,942	21,365
Interest payable	21,670	14,904
Deferred collaboration revenue	150	2,120
Lease financing obligation	1,179	1,377
Senior credit facility	0	9,020
Non-recourse notes payable	30,000	29,561
Total current liabilities	105,654	92,335
Royalty financing obligation	124,717	0
Lease financing obligation	3,871	3,406
Senior credit facility	0	41,289
Secured term loan	119,735	0
Stockholders’ equity:
Preferred stock, $0.01 par value; shares authorized — 5,000; no shares outstanding	0	0
Common stock, $0.01 par value; shares authorized — 450,000; shares issued and outstanding — 176,883 at December 31, 2020 and 154,082 at December 31, 2019	1,769	1,541
Additional paid-in capital	1,002,408	877,300
Accumulated other comprehensive income (loss)	3	39
Accumulated deficit	(1,023,442)	(840,628)
Total stockholders’ (deficit) equity	(19,262)	38,252
Total liabilities and stockholders’ equity	$ 334,715	$ 175,282

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares shares in Thousands	Dec. 31, 2020	Dec. 31, 2019
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000	5,000
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)	450,000	450,000
Common stock, shares issued (in shares)	176,883	154,082
Common stock, shares outstanding (in shares)	176,883	154,082

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Revenues	$ 17,812	$ 48,835	$ 20,653
Expenses
Cost of products sold	1,550	3,726
Research and development	122,964	107,068	84,888
Selling, general and administrative	67,929	37,121	29,514
Royalty	126	375	471
Total operating expenses	192,569	148,290	114,873
Loss from operations	(174,757)	(99,455)	(94,220)
Interest and other income	9,420	1,933	2,252
Interest expense	(14,501)	(11,892)	(9,176)
Loss on extinguishment of debt	(2,011)
Gain (loss) on foreign currency	(965)	517	(108)
Net loss	(182,814)	(108,897)	(101,252)
Unrealized gain (loss) on available for sale investments	(36)	336	(54)
Net comprehensive loss	$ (182,850)	$ (108,561)	$ (101,306)
Basic and diluted net loss per common share (in dollars per share)	$ (1.09)	$ (0.94)	$ (0.98)
Weighted average shares outstanding (in shares)	167,267	115,600	103,185
Product [Member]
Revenues:
Revenues	$ 3,301	$ 17,533
Royalty [Member]
Revenues:
Revenues	3,381	6,303	$ 6,101
Collaborative and Other Research and Development [Member]
Revenues:
Revenues	$ 11,130	$ 24,999	$ 14,552

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net loss	$ (182,814)	$ (108,897)	$ (101,252)
Depreciation and amortization	748	724	770
Loss (gain) on disposal of property and equipment			7
Stock-based compensation expense	14,794	17,719	9,396
Amortization of debt issuance costs	2,428	1,278	885
Amortization of premium/discount on investments	121	117	110
Change in fair value of foreign currency derivative	632	347	1,049
Receivables	13,903	(17,853)	1,824
Inventory	(7,039)	1,649	(1,649)
Prepaid expenses and other assets	(2,140)	(1,364)	(866)
Accounts payable and accrued expenses	17,355	11,741	4,487
Interest payable	6,766	3,056	(247)
Deferred revenue	(1,970)	1,899	(7,079)
Net cash used in operating activities:	(137,216)	(89,584)	(92,565)
Acquisition of property and equipment	(514)	(343)	(366)
Purchases of investments	(49,818)	(3,018)	(62,614)
Sales and maturities of investments	43,475	81,295	67,748
Realized gain on investments	1	0	0
Net cash provided by (used in) investing activities:	(6,856)	77,934	4,768
Sale of common stock, net	93,279	58,500	53,400
Sale of pre-funded warrants	14,817	19,882
Net proceeds from common stock issued under stock-based compensation plans	2,446	1,239	2,852
Proceeds from senior credit facility	0	19,477	10,353
Payment of senior credit facility	(52,420)		(4,025)
Net proceeds from secured term loan	119,867
Net proceeds from royalty financing obligation	124,708
(Decrease) increase in lease financing obligation			(76)
Net cash provided by financing activities:	302,697	99,098	62,504
Increase (decrease) in cash, cash equivalents and restricted cash	158,625	87,448	(25,293)
Cash, cash equivalents and restricted cash at beginning of year	115,723	28,275	53,568
Cash, cash equivalents and restricted cash at end of year	$ 274,348	$ 115,723	$ 28,275

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Cumulative Effect, Period of Adoption, Adjustment [Member]Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (Accounting Standards Update 2014-09 [Member]) at Dec. 31, 2017	$ 1,126	$ 1,126
Balance at Dec. 31, 2017			$ 984	$ 714,869	$ (243)	$ (631,843)	$ 83,767
Net loss						(101,252)	(101,252)
Other comprehensive income (loss)					(54)		(54)
Exercise of stock options, net			11	2,490			2,501
Employee stock purchase plan sales, net			1	350			351
Issuance of common stock, net			105	53,295			53,400
Stock-based compensation expense				9,396			9,396
Balance (Accounting Standards Update 2016-02 [Member]) at Dec. 31, 2018	$ 238	$ 238
Balance at Dec. 31, 2018			1,101	780,400	(297)	(731,969)	49,235
Net loss						(108,897)	(108,897)
Other comprehensive income (loss)					336		336
Exercise of stock options, net			3	832			835
Employee stock purchase plan sales, net			1	403			404
Issuance of common stock, net			436	58,064			58,500
Stock-based compensation expense				17,719			17,719
Issuance of pre-funded warrants				19,882			19,882
Balance at Dec. 31, 2019			1,541	877,300	39	(840,628)	38,252
Net loss						(182,814)	(182,814)
Other comprehensive income (loss)					(36)		(36)
Exercise of stock options, net			5	1,809			1,814
Employee stock purchase plan sales, net			3	629			632
Issuance of common stock, net			220	93,059			93,279
Stock-based compensation expense				14,794			14,794
Issuance of pre-funded warrants				14,817			14,817
Balance at Dec. 31, 2020			$ 1,769	$ 1,002,408	$ 3	$ (1,023,442)	$ (19,262)

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parentheticals) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Common Stock [Member]
Exercise of stock options, shares (in shares)	510,000	283,000
Employee stock purchase plan sales, shares (in shares)	246,000	115,000	92,000
Issuance of common stock, shares (in shares)	22,044,000	43,621,000	10,455,000
Warrants issued (in shares)	3,511,000	11,765,000

Note 1 - Significant Accounting

Note 1 - Significant Accounting Policies and Concentrations of Risk	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Significant Accounting Policies [Text Block]	Note 1 The Company BioCryst Pharmaceuticals, Inc. (the “Company”) is a commercial-stage biotechnology company that discovers novel, oral, small-molecule medicines. The Company focuses on the treatment of rare diseases in which significant unmet medical needs exist and an enzyme plays the key role in the biological pathway of the disease. The Company was founded in 1986 1991, Based on the Company’s expectations for revenue, operating expenses, and its option to access an additional $75 million from its existing credit facility, the Company believes its financial resources available at December 31, 2020 2023. 2021 2021 may 1 2 3 4 5 one 6 may Basis of Presentation The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances among the consolidated entities have been eliminated from the consolidated financial statements. The Company’s consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). Such consolidated financial statements reflect all adjustments that are, in management’s opinion, necessary to present fairly, in all material respects, the Company’s consolidated financial position, results of operations, and cash flows. There were no 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 Restricted Cash Restricted cash as of December 31, 2020 2019 3 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 three no may may not not not 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 three December 31, 2020, The following tables summarize the fair value of the Company’s investments by type. The estimated fair values of the Company’s fixed income investments are classified as Level 2 not not 2 December 31, 2020 Amortized Cost Accrued Interest Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Obligations of U.S. Government and its agencies $ 24,986 $ 14 $ 3 $ (3 ) $ 25,000 Certificates of deposit 3,225 11 3 − 3,239 Total Investments $ 28,211 $ 25 $ 6 $ (3 ) $ 28,239 December 31, 2019 Amortized Cost Accrued Interest Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Obligations of U.S. Government and its agencies $ 10,488 $ 50 $ 23 $ − $ 10,561 Corporate debt securities 9,742 59 10 (1 ) 9,810 Certificates of deposit 1,669 7 7 − 1,683 Total Investments $ 21,899 $ 116 $ 40 $ (1 ) $ 22,054 The Company’s investments at December 31, 2020 2019 one Receivables from Collaborations Receivables from collaborations are recorded for amounts due to the Company related to reimbursable research and development costs from the U.S. Department of Health and Human Services, royalty receivables from Shionogi, Green Cross Corporation (“Green Cross”), Mundipharma International Holdings Limited (“Mundipharma”) and Seqirus UK Limited (“SUL”), and product sales to SUL. These receivables are evaluated to determine if any reserve or allowance should be established at each reporting date December 31, 2020 2019 . At December 31, 2020 December 31, 2019, December 31, 20 20 Billed Unbilled Total U.S. Department of Health and Human Services $ − $ 5,402 $ 5,402 Shionogi & Co. Ltd. 2,037 4 2,041 Green Cross Corporation 740 21 761 Mundipharma International Holdings Limited 39 − 39 Total receivables $ 2,816 $ 5,427 $ 8,243 December 31, 2019 Billed Unbilled Total U.S. Department of Health and Human Services $ 1,353 $ 15,023 $ 16,376 Shionogi & Co. Ltd. 1,336 4 1,340 Green Cross Corporation 2,924 8 2,932 Mundipharma International Holdings Limited 56 - 56 Seqirus UK Limited 1,091 351 1,442 Total receivables $ 6,760 $ 15,386 $ 22,146 Monthly invoices are submitted to the U.S. Department of Health and Human Services related to reimbursable research and development costs. The Company is also entitled to monthly reimbursement of indirect costs based on rates stipulated in the underlying contract. The Company’s calculations of its indirect cost rates are subject to audit by the U.S. Government. Receivables from Product Sales Receivables December 31, 2020, December 31, 2019. December 31, 2020 . Inventory At December 31, 2020 2019, December 31, 2020, December 31, 2019, first first December 31, 2020 2019, The Company expenses costs related to the production of inventories as research and development expenses in the period incurred until such time it is believed that future economic benefit is expected to be recognized, which generally is reliant upon receipt of regulatory approval. Upon regulatory approval, the Company capitalizes subsequent costs related to the production of inventories. Property and Equipment Property and equipment are recorded at cost. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Computer equipment is depreciated over a life of three five seven 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 not 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 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 ● fees paid to Clinical Research Organizations (“CROs”) in connection with preclinical and toxicology studies and clinical trials; ● fees paid to investigative sites in connection with clinical trials; ● fees paid to contract manufacturers in connection with the production of the Company’s raw materials, drug substance, drug products, and product candidates; and ● professional fees. The Company bases its expenses related to clinical trials on its estimates of the services received and efforts expended pursuant to contracts with multiple research institutions and CROs that conduct and manage clinical trials on the Company’s behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may December 31, 2020 December 31, 2019, Accrued expenses were comprised of the following: December 31, 20 20 201 9 Compensation and benefits $ 11,030 $ 6,190 Development costs 15,150 11,302 Inventory 2,453 29 Professional fees 333 326 Duties and taxes 80 67 Other 4,896 3,451 Total accrued expenses $ 33,942 $ 21,365 Income Taxes The liability method is used in the Company’s accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. Accumulated Other Comprehensive Loss Accumulated other comprehensive loss is comprised of unrealized gains and losses on available-for-sale investments and is disclosed as a separate component of stockholders’ equity. Amounts reclassified from accumulated other comprehensive loss are recorded as interest and other income on the Consolidated Statements of Comprehensive Loss. For the year ended December 31, 2020, 2019. Revenue Recognition Collaborative and Other Research and Development Arrangements and Royalties The Company recognizes revenue when it satisfies a performance obligation by transferring promised goods or services to a customer. Revenue is measured at the transaction price that is based on the amount of consideration that the Company expects to receive in exchange for transferring the promised goods or services to the customer. The transaction price includes estimates of variable consideration to the extent it is probable that a significant reversal of revenue recognized will not The Company has collaboration and license agreements with a number of third Revenue from license fees, royalty payments, milestone payments, and research and development fees are recognized as revenue when the earnings process is complete and the Company has no Arrangements that involve the delivery of more than one not not may 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 Reimbursements received for direct out-of-pocket expenses related to research and development costs are recorded as revenue in the Consolidated Statements of Comprehensive Loss rather than as a reduction in expenses. Under the Company’s contracts with the Biomedical Advanced Research and Development Authority within the United States Department of Health and Human Services (”BARDA/HHS”) and the National Institute of Allergy and Infectious Diseases (“NIAID/HHS”), revenue is recognized as reimbursable direct and indirect costs are incurred. Under certain of the Company’s license agreements, the Company receives royalty payments based upon its licensees’ net sales of covered products. Royalties are recognized at the later of when (i) the subsequent sale or usage occurs, or (ii) the performance obligation to which some or all of the sales-based or usage-based royalty has been satisfied. Product Sales The Company’s principal sources of product sales are sales of peramivir to our licensing partners and sales of RAPIVAB to the U.S. Department of Health and Human Services under the Company’s procurement contract. In December 2020, The Company recorded the following revenues for the years ended December 31: 2020 2019 2018 Product sales, net $ 3,301 $ 17,533 $ − Royalty revenue 3,381 6,303 6,101 Collaborative and other research and development revenues: U.S. Department of Health and Human Services 9,231 4,898 2,552 Torii Pharmaceutical Co., Ltd. 1,899 20,101 − Seqirus UK Limited − − 12,000 Total collaborative and other research and development revenues 11,130 24,999 14,552 Total revenues $ 17,812 $ 48,835 $ 20,653 Advertising The Company engages in very limited distribution and direct-response advertising when promoting RAPIVAB. Advertising and promotional costs are expensed in “Selling, general and administrative” as the costs are incurred. Advertising expenses related to the launch of ORLADEYO were $6,567 for year ended December 31, 2020. not 2019 2018. Research and Development Expenses The Company’s research and development costs are charged to expense when incurred. Research and development expenses include all direct and indirect development costs related to the development of the Company’s portfolio of product candidates. Advance payments for goods or services that will be used or rendered for future research and development activities are deferred and capitalized. Such amounts are recognized as expense when the related goods are delivered or the related services are performed. Research and development expenses include, among other items, personnel costs, including salaries and benefits, manufacturing costs, clinical, regulatory, and toxicology services performed by CROs, materials and supplies, and overhead allocations consisting of various administrative and facilities related costs. Most of the Company’s manufacturing and clinical and preclinical studies are performed by third Additionally, the Company has license agreements with third Deferred collaboration expenses represent sub-license payments, paid to the Company’s academic partners upon receipt of consideration from various commercial partners, and other consideration paid to the Company’s academic partners for modification to existing license agreements. These deferred expenses would not 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 Interest Expense and Royalty Financing Obligation The royalty financing obligation is eligible to be repaid based on royalties from net sales of ORLADEYO. Interest expense is accrued using the effective interest rate method over the estimated period the related liability will be paid. This requires the Company to estimate the total amount of future royalty payments to be generated from product sales over the life of the agreement. The Company imputes interest on the carrying value of the royalty financing obligation and records interest expense using an imputed effective interest rate. The Company will reassess the expected royalty payments each reporting period and account for any changes through an adjustment to the effective interest rate on a prospective basis. The assumptions used in determining the expected repayment term of the debt and amortization period of the issuance costs requires that the Company make estimates that could impact the carrying value of the liability, as well as the period over which associated issuance costs will be amortized. A significant increase or decrease in forecasted net sales could materially impact the liability balance, interest expense and the time period for repayment. Interest Expense and Deferred Financing Costs Interest expense for the years ended December 31, 2020, 2019 2018 3 4 December 2020, 3 4 December 31, 2020, 2019 2018, December 2020, Currency Hedge Agreement In connection with the issuance by Royalty Sub of the PhaRMA Notes, the Company entered into a Currency Hedge Agreement to hedge certain risks associated with changes in the value of the Japanese yen relative to the U.S. dollar. The final tranche of the options under the Currency Hedge Agreement expired in November 2020. not December 31, 2020, 2019 2018 third not 2 2020, 2019 2018, Net Loss Per Share Net loss per share is based upon the weighted average number of common shares outstanding during the period. Diluted loss per share is equivalent to basic net loss per share for all periods presented herein because common equivalent shares from unexercised stock options, outstanding warrants, and common shares expected to be issued under the Company’s employee stock purchase plan were anti-dilutive. The calculation of diluted earnings per share for the years ended December 31, 2020, 2019, 2018 not Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. The most significant estimates in the Company’s consolidated financial statements relate to the valuation of stock options, and the valuation allowance for deferred tax assets resulting from net operating losses. These estimates are based on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not Significant Customers and Other Risks Significant Customers Other than royalty revenues, the Company’s primary sources of revenue that have an underlying cash flow stream are the reimbursement of galidesivir (formerly BCX4430 third Risks from Third Party Manufacturing and Distribution Concentration The Company relies on single source manufacturers for active pharmaceutical ingredient and finished drug product manufacturing of product candidates in development and on single source distributors for distribution of approved drug products. Delays in the manufacture or distribution of any product could adversely impact the commercial revenue and future procurement stockpiling of the Company’s product candidates in development. Credit Risk Cash equivalents and investments are financial instruments which potentially subject the Company to concentration of risk to the extent recorded on the Consolidated Balance Sheets. The Company deposits excess cash with major financial institutions in the United States. Balances may no Recent Accounting Pronouncements In June 2016, No. 2016 13, Financial Instruments - Credit Losses (Topic 326 Credit Losses on Financial Instruments 2016 13” . 2016 13 2016 13 2016 13 2016 13 December 15, 2019. 2016 02 January 1, 2020. not In August 2018, No. 2018 15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350 40 2018 15” 2018 15 2018 15 December 15, 2019, October 1, 2019 not The Company has reviewed other new accounting pronouncements that were issued as of December 31, 2020 not

Note 2 - Property and Equipment

Note 2 - Property and Equipment	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Property, Plant and Equipment Disclosure [Text Block]	Note 2 Property and equipment consisted of the following at December 31: 20 20 201 9 Furniture and fixtures $ 722 $ 602 Office equipment 211 184 Software 1,159 1,159 Laboratory equipment 3,774 3,462 Leasehold improvements 8,583 8,528 14,449 13,935 Less accumulated depreciation and amortization (7,336 ) (6,588 ) Property and equipment, net $ 7,113 $ 7,347 Depreciation and amortization expense for the years ended December 31, 2020, 2019, 2018

Note 3 - Royalty Monetizations

Note 3 - Royalty Monetizations	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Royalty Monetization [Text Block]	Note 3—Royalty RAPIACTA Royalty Monetization s Overview On March 9, 2011, September 2012 . As March 9, 2011 not . Non-Recourse Notes Payable On March 9, 2011, December 1, 2020 ( March 9, 2011 ( September 1st 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, not may one In September 2014, September 3, 2013. September 2013 September 1, 2014, December 31, 2014 may may not not December 1, 2020, December 31, 2020, no The Indenture does not As of December 31, 2020, 3 Foreign Currency Hedge In connection with the issuance by Royalty Sub of the PhaRMA Notes, the Company entered into a Currency Hedge Agreement to hedge certain risks associated with changes in the value of the Japanese yen relative to the U.S. dollar. Under the Currency Hedge Agreement, the Company had the right to purchase dollars and sell yen at a rate of 100 yen per dollar. The final tranche of the options under the Currency Hedge Agreement expired in November 2020. The Currency Hedge Agreement did not 2020, 2019 2018 2020, 2019 2018, ORLADEYO Royalty Monetization On December 7, 2020, 2019 $350,000 $350,000 $550,000. $550,000. BCX9930. Under the Royalty Purchase Agreement, RPI is also entitled to receive a tiered revenue share on ORLADEYO sublicense revenue or net sales by licensees outside of the Key Territories (the “Other Markets”) equal to: (i) 20% of the proceeds received by the Company for upfront license fees and development milestones for ORLADEYO in the Other Markets; (ii) 20% of proceeds received on annual net sales of up to $150,000 $150,000 $230,000 $230,000 No may The Company will be required to make royalty payments of amounts owed to RPI each calendar quarter following the first Under the Royalty Purchase Agreement, the Company has agreed to specified affirmative and negative covenants, including covenants regarding periodic reporting of information by the Company to RPI, third 1 4 The cash consideration of $125,000 obtained pursuant to the Royalty Purchase Agreement is recorded in “Royalty financing obligation” on the Company’s consolidated balance sheet as of December 31, 2020. 3 December 31, 2020. December 31, 2020 2020,

Note 4 - Credit Agreement

Note 4 - Credit Agreement	12 Months Ended
	Dec. 31, 2020
Senior Credit Facility [Member]
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 5 — Senior Credit Facility On February 5, 2019, three first second third second third September 10, 2019 first second November 30, 2019. November 30, 2019, second The Second Amended and Restated Senior Credit Facility refinanced and replaced the Amended and Restated Senior Credit Facility dated as of July 20, 2018 ( not June 2020 In December 2020,
Credit Agreement [Member]
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 4 — Credit Agreement On December 7, 2020, 1 December 7, 2020 December 31, 2020. BCX9930 The Credit Agreement also provides for two may December 7, 2025. The Credit Agreement provides for quarterly interest-only payments until the maturity date, with the unpaid principal amount of the outstanding Term Loans due and payable on the maturity date. For each of the first eight December 7, 2020, three no no Subject to certain exceptions, the Company is required to make mandatory prepayments of the Term Loans with the proceeds of certain asset sales, certain ORLADEYO out-licensing or royalty monetization transactions (excluding the Royalty Sale), extraordinary receipts, debt issuances, or upon a change of control of the Company and specified other events, subject to certain exceptions. The Company may second 1 2 second second third third fourth , 1.00% of the principal amount of the Term Loan being prepaid; and (iv) with respect to any prepayment made after the fourth The Credit Agreement also contains representations and warranties and affirmative and negative covenants customary for financings of this type, as well as customary events of default. Certain of the customary negative covenants limit the ability of the Company and certain of its subsidiaries to, among other things, grant liens, make investments, incur additional indebtedness, engage in mergers, acquisitions, and similar transactions, dispose of assets, license certain property, distribute dividends, make certain restricted payments, change the nature of the Company's business, engage in transactions with affiliates and insiders, prepay other indebtedness, or engage in sale and leaseback transactions, subject to certain exceptions. Additionally, as of the last day of each fiscal quarter (a “Test Date”), beginning with the first may not four one not A failure to comply with the covenants in the Credit Agreement could permit the Lenders under the Credit Agreement to declare the outstanding principal as well as accrued interest and fees, to be immediately due and payable. The Company's obligations under the Credit Agreement are secured by a security interest in, subject to certain exceptions, substantially all of the Company's assets. As of December 31, 2020, The Credit Agreement provides for quarterly interest-only payments until the maturity date, with the unpaid principal amount of the outstanding Term Loans due and payable on the maturity date of December 7, 2025. first December 31, 2020, 2020 The Credit Agreement contains two not

Note 5 - Senior Credit Facility

Note 5 - Senior Credit Facility	12 Months Ended
	Dec. 31, 2020
Senior Credit Facility [Member]
Notes to Financial Statements
Debt Disclosure [Text Block]	Note 5 — Senior Credit Facility On February 5, 2019, three first second third second third September 10, 2019 first second November 30, 2019. November 30, 2019, second The Second Amended and Restated Senior Credit Facility refinanced and replaced the Amended and Restated Senior Credit Facility dated as of July 20, 2018 ( not June 2020 In December 2020,

Note 6 - Lease Obligations and

Note 6 - Lease Obligations and Other Contingencies	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Leases of Lessor Disclosure [Text Block]	Note 6 — Lease Obligations and Other Contingencies In February 2016, 2016 02: Leases (Topic 842 2016 02 December 15, 2018, July 2018, 2018 11, Leases (Topic 842 January 1, 2019 The Company elected the package of practical expedients referenced in ASU 2016 02, twelve not January 1, 2019 no The Company leases certain assets under operating leases, which primarily consisted of real estate leases, laboratory equipment leases and office equipment leases as of December 31, 2020. 2023 2026. The Company has not no Aggregate lease expense under operating leases was $1,754 and $1,464 for the twelve December 31, 2020 2019, twelve not Future lease payments for assets under operating leases as of December 31, 2020, Remaining Maturities of Lease Liabilities Year Ending December 31, Operating Leases 2021 $ 1,302 2022 758 2023 619 2024 577 2025 582 Thereafter 7,327 Total lease payments 11,165 Less imputed interest 6,115 Total $ 5,050 The December 31, 2020 2019 December 31, 2020 2019 December 31, 2020 2019, December 31, 2020 2019, December 31, 2020 2019, .

Note 7 - Stockholders' Equity

Note 7 - Stockholders' Equity	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Stockholders' Equity Note Disclosure [Text Block]	Note 7 — Stockholders’ Equity Sales of Common Stock On November 8, 2017, 3 December 12, 2017 On August 6, 2018, 30 On November 18, 2019, 30 On November 21, 2019, 1 may December 31, 2020. On April 24, 2020, 3 May 14, 2020 On June 1, 2020, 1 December 31, 2020.

Note 8 - Stock-based Compensati

Note 8 - Stock-based Compensation	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Share-based Payment Arrangement [Text Block]	Note 8 — Stock-Based Compensation As of December 31, 2020, three Inducement Equity Incentive Plan (“Inducement Plan”) and the Employee Stock Purchase Plan (“ESPP”). The Incentive Plan was amended and restated on March 19, 2020 May 12, 2020. April 24, 2019 February 2020 July 2020. March 2020 May 12, 2020. 2020, 2019 2018. The Company accounts for stock-based compensation in accordance with FASB authoritative guidance regarding share-based payments. Total stock-based compensation was allocated as follows: Year Ended December 31, 20 20 201 9 201 8 Research and development $ 10,222 $ 13,977 $ 6,867 Selling, general and administrative 4,572 3,742 2,529 Total stock-based compensation expense $ 14,794 $ 17,719 $ 9,396 Stock Incentive Plan The Company grants stock option awards and restricted stock unit awards to its employees, directors, and consultants under the Incentive Plan. Under the Incentive Plan, stock option awards are granted with an exercise price equal to the market price of the Company’s stock at the date of grant. Commencing March 1, 2011, four August 2013, December 2014 December 2019, December 31, 2020, August 2013, December 2014 December 2019 2020, August 2013 December 2019 one Related activity under the Incentive Plan is as follows: Weighted Average Awards Options Exercise Available Outstanding Price Balance at December 31, 2017 468 14,452 $ 6.06 Plan amendment 4,400 − − Restricted stock awards granted (13 ) − − Stock option awards granted (4,272 ) 4,272 7.15 Stock option awards exercised − (1,011 ) 2.92 Stock option awards cancelled 222 (222 ) 7.44 Balance at December 31, 2018 805 17,491 6.49 Plan amendment 4,000 − − Restricted stock awards granted (27 ) − − Stock option awards granted (4,511 ) 4,511 3.91 Stock option awards exercised − (251 ) 3.75 Stock option awards cancelled 701 (701 ) 6.82 Balance at December 31, 2019 968 21,050 5.96 Plan amendment 8,000 − − Restricted stock awards granted (31 ) − − Stock option awards granted (7,469 ) 7,469 8.06 Stock option awards exercised − (510 ) 3.56 Stock option awards cancelled 3,124 (3,124 ) 6.93 Balance at December 31, 2020 4,592 24,885 $ 6.52 For stock option awards granted under the Incentive Plan during 2020, 2019, 2018, 2020, 2019, 2018 Inducement Equity Incentive Plan The four . Related activity under the Inducement Plan is as follows: Weighted Average Awards Options Exercise Available Outstanding Price Balance at December 31, 2019 171 1,329 $ 3.60 Plan amendment 2,900 − − Stock option awards granted (3,002 ) 3,002 4.02 Stock option awards cancelled 160 (160 ) 4.15 Balance at December 31, 2020 229 4,171 $ 3.88 For stock option awards granted under the Inducement Plan during 2020 2019, 2020 2019 The following table summarizes the key assumptions used by the Company to value the stock option awards granted under all plans during 2020, 2019, 2018, not not zero Weighted Average Assumptions for Stock Option Awards Granted to Employees and Directors under the Plans 20 20 201 9 201 8 Expected Life 5.5 5.5 5.5 Expected Volatility 84 % 81 % 82 % Expected Dividend Yield 0.0 % 0.0 % 0.0 % Risk-Free Interest Rate 0.4 % 1.8 % 2.7 % The total intrinsic value of stock option awards exercised under the Incentive Plan was $1,562 during 2020, 2019, 2018. 2020. The following table summarizes, at December 31, 2020, 1 2 Outstanding Exercisable Weighted Weighted Weighted Average Average Average Remaining Exercise Exercise Range Number Life Price Number Price $ 0 to 3 2,514 6.1 $ 2.19 1,414 $ 1.25 3 to 6 12,689 7.0 4.22 6,854 2.48 6 to 9 10,852 9.2 7.88 2,005 4.89 9 to 12 2,347 4.5 10.85 2,129 4.51 12 to 15 559 4.1 12.30 539 6.43 15 to 18 95 4.5 15.39 95 10.57 $ 0 to 18 29,056 7.5 $ 6.14 13,036 $ 3.27 The weighted average remaining contractual life of stock option awards exercisable under the plans at December 31, 2020 The aggregate intrinsic value of stock option awards outstanding and exercisable under the plans at December 31, 2020 The total fair value of the stock option awards vested under the plans was $18,739 during 2020, 2019, 2018. As December 31, 2020, . The following table summarizes the changes in the number and weighted-average grant-date fair value of non-vested stock option awards during 2020: Non-Vested Stock Option Awards Weighted Average Grant-Date Fair Value Balance December 31, 2019 11,688 $ 3.77 Stock option awards granted 10,471 4.69 Stock option awards vested (4,543 ) 4.12 Stock option awards forfeited (1,596 ) 3.96 Balance December 31, 2020 16,020 $ 4.25 As of December 31, 2020, 2021, 2022, 2023, 2024. Employee Stock Purchase Plan The Company has reserved a total of 4,475 shares of common stock to be purchased under the ESPP, of which 2,873 shares remain available for purchase at December 31, 2020. may six No may one six no may one There were 246, 115, and 92 shares of common stock purchased under the ESPP in 2020, 2019, 2018, 2020, 2019, 2018, 2020, 2019, 2018,

Note 9 - Income Taxes

Note 9 - Income Taxes	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Income Tax Disclosure [Text Block]	Note 9 — Income Taxes The Company has incurred net losses since inception and, consequently, has not The components of loss before provision for income taxes were as followings: 2020 Domestic $ (176,613 ) Foreign (6,201 ) Loss before provision for income taxes $ (182,814 ) The differences between the Company’s effective tax rate and the statutory tax rate in 2020, 2019, 2018, 20 20 201 9 201 8 Income tax benefit at federal statutory rate ( 21% $ (38,391 ) $ (22,868 ) $ (21,263 ) State and local income taxes net of federal tax benefit (2,544 ) (1,591 ) (2,547 ) Permanent items 774 691 503 Rate change (82 ) 625 (29 ) Expiration of attribute carryforwards 3,774 3,976 2,183 Research and development tax credits (4,080 ) (4,938 ) (4,905 ) Foreign rate differential 542 - - Other 1,456 281 18 Change in valuation allowance 38,551 23,824 26,040 Income tax expense $ - $ - $ - The Company recognizes the impact of a tax position in its financial statements if it is more likely than not no not 12 A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: 20 20 201 9 Balance at January 1, $ 7,210 $ 5,976 Additions to current period tax positions 1,020 1,234 Additions to prior period tax positions − − Reductions to prior period tax provisions − − Balance at December 31, $ 8,230 $ 7,210 The Company’s ability to utilize the net operating loss and tax credit carryforwards in the future may 382 1986, Significant components of the Company’s deferred tax assets and liabilities are as follows: 20 20 201 9 Deferred tax assets: Net federal and state operating losses $ 159,939 $ 155,190 Research and development credits 66,331 63,275 Royalty income 28,034 - Stock-based compensation 10,732 9,786 Leasing obligations 1,135 1,070 Other 5,563 3,801 Total deferred tax assets 271,734 233,122 Deferred tax liabilities: Fixed assets (124 ) (114 ) Right of use asset (854 ) (803 ) Total deferred tax liabilities (978 ) (917 ) Valuation allowance (270,756 ) (232,205 ) Net deferred tax assets $ − $ − The majority of the Company’s deferred tax assets relate to net operating loss and research and development carryforwards that can only be realized if the Company is profitable in future periods. It is uncertain whether the Company will realize any tax benefit related to these carryforwards. Accordingly, the Company has provided a full valuation allowance against the net deferred tax assets due to uncertainties as to their ultimate realization. The valuation allowance will remain at the full amount of the deferred tax assets until it is more likely than not 2020, 2019, 2018, As of December 31, 2020, 2021 2040. 2020. Tax years 2017 2020 2017 2020, 2019 2018.

Note 10 - Employee 401(k) Plan

Note 10 - Employee 401(k) Plan	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Retirement Benefits [Text Block]	Note 10 — Employee 401 In January 1991, “401 401 may 401 may 2020, 2019, 2018,

Note 11 - Collaborative and Oth

Note 11 - Collaborative and Other Research and Development Contracts	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Collaborative Arrangement Disclosure [Text Block]	Note 11 — Collaborative and Other Research and Development Contracts National Institute of Allergy and Infectious Diseases (“NIAID/HHS”) September 2013, December 31, 2020, $2,897 August 2020 August 2020, . Biomedical Advanced Research and Development Authority (“BARDA/HHS”) March 2015, December 31, 2020, The contracts with NIAID/HHS and BARDA/HHS are cost-plus-fixed-fee contracts. That is, the Company is entitled to receive reimbursement for all costs incurred in accordance with the contract provisions that are related to the development of galidesivir plus a fixed fee, or profit. BARDA/HHS and NIAID/HHS will make periodic assessments of progress, and the continuation of the contract is based on the Company’s performance, the timeliness and quality of deliverables, and other factors. The government has rights under certain contract clauses to terminate these contracts. These contracts are terminable by the government at any time for breach or without cause. U.S. Department of Health and Human Services (“HHS”) September 2018, 50,000 five 10,000 September 2019, 10,000 20,000 2019. September 3, 2020, 10,000 2021. No 2020 10,000 . Torii Pharmaceutical Co., Ltd. (“Torii”) November 5, 2019, Under the Torii Agreement, the Company received an upfront, non-refundable payment of $22,000 and is eligible to receive an additional milestone payment of $15,000 upon receipt from Japan’s National Health Insurance System of a reimbursement price approval for ORLADEYO in excess of the threshold specified in the Torii Agreement. In addition, under the Torii Agreement, the Company is entitled to receive tiered royalty payments, ranging from 20% to 40% of annual net sales of ORLADEYO in Japan during each calendar year. Torii’s royalty payment obligations are subject to customary reductions in certain circumstances, but may not first tenth first Under the Torii Agreement, the Company has granted Torii a right of first may not third The Company identified performance obligations related to (i) the license to develop and commercialize ORLADEYO, (ii) regulatory approval support and (iii) reimbursement pricing approval support. These were each determined to be distinct from the other performance obligations. The Company allocated the $22,000 606. 2019 2020 two $22,000 2020 Seqirus UK Limited (“SUL”). June 16, 2015, On March 4, 2020, August 1, 2020 November 1, 2020, 30 December 31, 2020. Shionogi & Co., Ltd. (“Shionogi”). February 2007, October 2008, In December 2017, no Green Cross Corporation (“Green Cross”). June 2006, one Mundipharma International Holdings Limited (“Mundipharma”). February 2006, Albert Einstein College of Medicine of Yeshiva University and Industrial Research, Ltd. (“AECOM” and “IRL” respectively). June 2000, third The University of Alabama at Birmingham (“UAB”). third two five three no

Note 12 - Quarterly Financial I

Note 12 - Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2020
Notes to Financial Statements
Quarterly Financial Information [Text Block]	Note 12 — Quarterly Financial Information (Unaudited) First Second Third Fourth 20 20 Quarters Revenues $ 4,823 $ 2,871 $ 6,102 $ 4,016 Net Loss (37,599 ) (38,607 ) (46,115 ) (60,493 ) Basic and diluted net loss per share (0.24 ) (0.24 ) (0.26 ) (0.34 ) 2019 Quarters Revenues $ 5,887 $ 1,448 $ 1,775 $ 39,725 Net Loss (31,054 ) (37,629 ) (37,592 ) (2,622 ) Basic and diluted net loss per share (0.28 ) (0.34 ) (0.34 ) (0.02 )

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Description of Company [Policy Text Block]	The Company BioCryst Pharmaceuticals, Inc. (the “Company”) is a commercial-stage biotechnology company that discovers novel, oral, small-molecule medicines. The Company focuses on the treatment of rare diseases in which significant unmet medical needs exist and an enzyme plays the key role in the biological pathway of the disease. The Company was founded in 1986 1991, Based on the Company’s expectations for revenue, operating expenses, and its option to access an additional $75 million from its existing credit facility, the Company believes its financial resources available at December 31, 2020 2023. 2021 2021 may 1 2 3 4 5 one 6 may
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany transactions and balances among the consolidated entities have been eliminated from the consolidated financial statements. The Company’s consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). Such consolidated financial statements reflect all adjustments that are, in management’s opinion, necessary to present fairly, in all material respects, the Company’s consolidated financial position, results of operations, and cash flows. There were no
Cash and Cash Equivalents, Policy [Policy Text Block]	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
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	Restricted Cash Restricted cash as of December 31, 2020 2019 3
Investment, Policy [Policy Text Block]	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 three no may may not not not 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 three December 31, 2020, The following tables summarize the fair value of the Company’s investments by type. The estimated fair values of the Company’s fixed income investments are classified as Level 2 not not 2 December 31, 2020 Amortized Cost Accrued Interest Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Obligations of U.S. Government and its agencies $ 24,986 $ 14 $ 3 $ (3 ) $ 25,000 Certificates of deposit 3,225 11 3 − 3,239 Total Investments $ 28,211 $ 25 $ 6 $ (3 ) $ 28,239 December 31, 2019 Amortized Cost Accrued Interest Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Obligations of U.S. Government and its agencies $ 10,488 $ 50 $ 23 $ − $ 10,561 Corporate debt securities 9,742 59 10 (1 ) 9,810 Certificates of deposit 1,669 7 7 − 1,683 Total Investments $ 21,899 $ 116 $ 40 $ (1 ) $ 22,054 The Company’s investments at December 31, 2020 2019 one
Receivable [Policy Text Block]	Receivables from Collaborations Receivables from collaborations are recorded for amounts due to the Company related to reimbursable research and development costs from the U.S. Department of Health and Human Services, royalty receivables from Shionogi, Green Cross Corporation (“Green Cross”), Mundipharma International Holdings Limited (“Mundipharma”) and Seqirus UK Limited (“SUL”), and product sales to SUL. These receivables are evaluated to determine if any reserve or allowance should be established at each reporting date December 31, 2020 2019 . At December 31, 2020 December 31, 2019, December 31, 20 20 Billed Unbilled Total U.S. Department of Health and Human Services $ − $ 5,402 $ 5,402 Shionogi & Co. Ltd. 2,037 4 2,041 Green Cross Corporation 740 21 761 Mundipharma International Holdings Limited 39 − 39 Total receivables $ 2,816 $ 5,427 $ 8,243 December 31, 2019 Billed Unbilled Total U.S. Department of Health and Human Services $ 1,353 $ 15,023 $ 16,376 Shionogi & Co. Ltd. 1,336 4 1,340 Green Cross Corporation 2,924 8 2,932 Mundipharma International Holdings Limited 56 - 56 Seqirus UK Limited 1,091 351 1,442 Total receivables $ 6,760 $ 15,386 $ 22,146 Monthly invoices are submitted to the U.S. Department of Health and Human Services related to reimbursable research and development costs. The Company is also entitled to monthly reimbursement of indirect costs based on rates stipulated in the underlying contract. The Company’s calculations of its indirect cost rates are subject to audit by the U.S. Government. Receivables from Product Sales Receivables December 31, 2020, December 31, 2019. December 31, 2020 .
Inventory, Policy [Policy Text Block]	Inventory At December 31, 2020 2019, December 31, 2020, December 31, 2019, first first December 31, 2020 2019, The Company expenses costs related to the production of inventories as research and development expenses in the period incurred until such time it is believed that future economic benefit is expected to be recognized, which generally is reliant upon receipt of regulatory approval. Upon regulatory approval, the Company capitalizes subsequent costs related to the production of inventories.
Property, Plant and Equipment, Policy [Policy Text Block]	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 five seven 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 not
Intangible Assets, Finite-Lived, Policy [Policy Text Block]	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 [Policy Text Block]	Accrued Expenses The Company generally enters into contractual agreements with third 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 ● fees paid to Clinical Research Organizations (“CROs”) in connection with preclinical and toxicology studies and clinical trials; ● fees paid to investigative sites in connection with clinical trials; ● fees paid to contract manufacturers in connection with the production of the Company’s raw materials, drug substance, drug products, and product candidates; and ● professional fees. The Company bases its expenses related to clinical trials on its estimates of the services received and efforts expended pursuant to contracts with multiple research institutions and CROs that conduct and manage clinical trials on the Company’s behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may December 31, 2020 December 31, 2019, Accrued expenses were comprised of the following: December 31, 20 20 201 9 Compensation and benefits $ 11,030 $ 6,190 Development costs 15,150 11,302 Inventory 2,453 29 Professional fees 333 326 Duties and taxes 80 67 Other 4,896 3,451 Total accrued expenses $ 33,942 $ 21,365
Income Tax, Policy [Policy Text Block]	Income Taxes 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.
Comprehensive Income, Policy [Policy Text Block]	Accumulated Other Comprehensive Loss Accumulated other comprehensive loss is comprised of unrealized gains and losses on available-for-sale investments and is disclosed as a separate component of stockholders’ equity. Amounts reclassified from accumulated other comprehensive loss are recorded as interest and other income on the Consolidated Statements of Comprehensive Loss. For the year ended December 31, 2020, 2019.
Revenue [Policy Text Block]	Revenue Recognition Collaborative and Other Research and Development Arrangements and Royalties The Company recognizes revenue when it satisfies a performance obligation by transferring promised goods or services to a customer. Revenue is measured at the transaction price that is based on the amount of consideration that the Company expects to receive in exchange for transferring the promised goods or services to the customer. The transaction price includes estimates of variable consideration to the extent it is probable that a significant reversal of revenue recognized will not The Company has collaboration and license agreements with a number of third Revenue from license fees, royalty payments, milestone payments, and research and development fees are recognized as revenue when the earnings process is complete and the Company has no Arrangements that involve the delivery of more than one not not may 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 Reimbursements received for direct out-of-pocket expenses related to research and development costs are recorded as revenue in the Consolidated Statements of Comprehensive Loss rather than as a reduction in expenses. Under the Company’s contracts with the Biomedical Advanced Research and Development Authority within the United States Department of Health and Human Services (”BARDA/HHS”) and the National Institute of Allergy and Infectious Diseases (“NIAID/HHS”), revenue is recognized as reimbursable direct and indirect costs are incurred. Under certain of the Company’s license agreements, the Company receives royalty payments based upon its licensees’ net sales of covered products. Royalties are recognized at the later of when (i) the subsequent sale or usage occurs, or (ii) the performance obligation to which some or all of the sales-based or usage-based royalty has been satisfied. Product Sales The Company’s principal sources of product sales are sales of peramivir to our licensing partners and sales of RAPIVAB to the U.S. Department of Health and Human Services under the Company’s procurement contract. In December 2020, The Company recorded the following revenues for the years ended December 31: 2020 2019 2018 Product sales, net $ 3,301 $ 17,533 $ − Royalty revenue 3,381 6,303 6,101 Collaborative and other research and development revenues: U.S. Department of Health and Human Services 9,231 4,898 2,552 Torii Pharmaceutical Co., Ltd. 1,899 20,101 − Seqirus UK Limited − − 12,000 Total collaborative and other research and development revenues 11,130 24,999 14,552 Total revenues $ 17,812 $ 48,835 $ 20,653 Advertising The Company engages in very limited distribution and direct-response advertising when promoting RAPIVAB. Advertising and promotional costs are expensed in “Selling, general and administrative” as the costs are incurred. Advertising expenses related to the launch of ORLADEYO were $6,567 for year ended December 31, 2020. not 2019 2018.
Research and Development Expense, Policy [Policy Text Block]	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 Additionally, the Company has license agreements with third Deferred collaboration expenses represent sub-license payments, paid to the Company’s academic partners upon receipt of consideration from various commercial partners, and other consideration paid to the Company’s academic partners for modification to existing license agreements. These deferred expenses would not
Share-based Payment Arrangement [Policy Text Block]	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
Interest Expense and Royalty Financing Obligation [Policy Text Block]	Interest Expense and Royalty Financing Obligation The royalty financing obligation is eligible to be repaid based on royalties from net sales of ORLADEYO. Interest expense is accrued using the effective interest rate method over the estimated period the related liability will be paid. This requires the Company to estimate the total amount of future royalty payments to be generated from product sales over the life of the agreement. The Company imputes interest on the carrying value of the royalty financing obligation and records interest expense using an imputed effective interest rate. The Company will reassess the expected royalty payments each reporting period and account for any changes through an adjustment to the effective interest rate on a prospective basis. The assumptions used in determining the expected repayment term of the debt and amortization period of the issuance costs requires that the Company make estimates that could impact the carrying value of the liability, as well as the period over which associated issuance costs will be amortized. A significant increase or decrease in forecasted net sales could materially impact the liability balance, interest expense and the time period for repayment.
Interest Expense and Deferred Financing Costs [Policy Text Block]	Interest Expense and Deferred Financing Costs Interest expense for the years ended December 31, 2020, 2019 2018 3 4 December 2020, 3 4 December 31, 2020, 2019 2018, December 2020,
Currency Hedge Agreement [Policy Text Block]	Currency Hedge Agreement In connection with the issuance by Royalty Sub of the PhaRMA Notes, the Company entered into a Currency Hedge Agreement to hedge certain risks associated with changes in the value of the Japanese yen relative to the U.S. dollar. The final tranche of the options under the Currency Hedge Agreement expired in November 2020. not December 31, 2020, 2019 2018 third not 2 2020, 2019 2018,
Earnings Per Share, Policy [Policy Text Block]	Net Loss Per Share Net loss per share is based upon the weighted average number of common shares outstanding during the period. Diluted loss per share is equivalent to basic net loss per share for all periods presented herein because common equivalent shares from unexercised stock options, outstanding warrants, and common shares expected to be issued under the Company’s employee stock purchase plan were anti-dilutive. The calculation of diluted earnings per share for the years ended December 31, 2020, 2019, 2018 not
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. The most significant estimates in the Company’s consolidated financial statements relate to the valuation of stock options, and the valuation allowance for deferred tax assets resulting from net operating losses. These estimates are based on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not
Concentration of Market Risk [Policy Text Block]	Significant Customers and Other Risks Significant Customers Other than royalty revenues, the Company’s primary sources of revenue that have an underlying cash flow stream are the reimbursement of galidesivir (formerly BCX4430 third Risks from Third Party Manufacturing and Distribution Concentration The Company relies on single source manufacturers for active pharmaceutical ingredient and finished drug product manufacturing of product candidates in development and on single source distributors for distribution of approved drug products. Delays in the manufacture or distribution of any product could adversely impact the commercial revenue and future procurement stockpiling of the Company’s product candidates in development. Credit Risk Cash equivalents and investments are financial instruments which potentially subject the Company to concentration of risk to the extent recorded on the Consolidated Balance Sheets. The Company deposits excess cash with major financial institutions in the United States. Balances may no
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In June 2016, No. 2016 13, Financial Instruments - Credit Losses (Topic 326 Credit Losses on Financial Instruments 2016 13” . 2016 13 2016 13 2016 13 2016 13 December 15, 2019. 2016 02 January 1, 2020. not In August 2018, No. 2018 15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350 40 2018 15” 2018 15 2018 15 December 15, 2019, October 1, 2019 not The Company has reviewed other new accounting pronouncements that were issued as of December 31, 2020 not

Note 1 - Significant Accounti_2

Note 1 - Significant Accounting Policies and Concentrations of Risk (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Debt Securities, Available-for-sale [Table Text Block]	December 31, 2020 Amortized Cost Accrued Interest Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Obligations of U.S. Government and its agencies $ 24,986 $ 14 $ 3 $ (3 ) $ 25,000 Certificates of deposit 3,225 11 3 − 3,239 Total Investments $ 28,211 $ 25 $ 6 $ (3 ) $ 28,239 December 31, 2019 Amortized Cost Accrued Interest Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Obligations of U.S. Government and its agencies $ 10,488 $ 50 $ 23 $ − $ 10,561 Corporate debt securities 9,742 59 10 (1 ) 9,810 Certificates of deposit 1,669 7 7 − 1,683 Total Investments $ 21,899 $ 116 $ 40 $ (1 ) $ 22,054
Schedule of Receivables from Collaborations [Table Text Block]	December 31, 20 20 Billed Unbilled Total U.S. Department of Health and Human Services $ − $ 5,402 $ 5,402 Shionogi & Co. Ltd. 2,037 4 2,041 Green Cross Corporation 740 21 761 Mundipharma International Holdings Limited 39 − 39 Total receivables $ 2,816 $ 5,427 $ 8,243 December 31, 2019 Billed Unbilled Total U.S. Department of Health and Human Services $ 1,353 $ 15,023 $ 16,376 Shionogi & Co. Ltd. 1,336 4 1,340 Green Cross Corporation 2,924 8 2,932 Mundipharma International Holdings Limited 56 - 56 Seqirus UK Limited 1,091 351 1,442 Total receivables $ 6,760 $ 15,386 $ 22,146
Schedule of Accrued Liabilities [Table Text Block]	December 31, 20 20 201 9 Compensation and benefits $ 11,030 $ 6,190 Development costs 15,150 11,302 Inventory 2,453 29 Professional fees 333 326 Duties and taxes 80 67 Other 4,896 3,451 Total accrued expenses $ 33,942 $ 21,365
Disaggregation of Revenue [Table Text Block]	2020 2019 2018 Product sales, net $ 3,301 $ 17,533 $ − Royalty revenue 3,381 6,303 6,101 Collaborative and other research and development revenues: U.S. Department of Health and Human Services 9,231 4,898 2,552 Torii Pharmaceutical Co., Ltd. 1,899 20,101 − Seqirus UK Limited − − 12,000 Total collaborative and other research and development revenues 11,130 24,999 14,552 Total revenues $ 17,812 $ 48,835 $ 20,653

Note 2 - Property and Equipme_2

Note 2 - Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Property, Plant and Equipment [Table Text Block]	20 20 201 9 Furniture and fixtures $ 722 $ 602 Office equipment 211 184 Software 1,159 1,159 Laboratory equipment 3,774 3,462 Leasehold improvements 8,583 8,528 14,449 13,935 Less accumulated depreciation and amortization (7,336 ) (6,588 ) Property and equipment, net $ 7,113 $ 7,347

Note 6 - Lease Obligations an_2

Note 6 - Lease Obligations and Other Contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Lessee, Lease, Liability, Maturity [Table Text Block]	Remaining Maturities of Lease Liabilities Year Ending December 31, Operating Leases 2021 $ 1,302 2022 758 2023 619 2024 577 2025 582 Thereafter 7,327 Total lease payments 11,165 Less imputed interest 6,115 Total $ 5,050

Note 8 - Stock-based Compensa_2

Note 8 - Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]	Year Ended December 31, 20 20 201 9 201 8 Research and development $ 10,222 $ 13,977 $ 6,867 Selling, general and administrative 4,572 3,742 2,529 Total stock-based compensation expense $ 14,794 $ 17,719 $ 9,396
Share-based Payment Arrangement, Activity [Table Text Block]	Weighted Average Awards Options Exercise Available Outstanding Price Balance at December 31, 2017 468 14,452 $ 6.06 Plan amendment 4,400 − − Restricted stock awards granted (13 ) − − Stock option awards granted (4,272 ) 4,272 7.15 Stock option awards exercised − (1,011 ) 2.92 Stock option awards cancelled 222 (222 ) 7.44 Balance at December 31, 2018 805 17,491 6.49 Plan amendment 4,000 − − Restricted stock awards granted (27 ) − − Stock option awards granted (4,511 ) 4,511 3.91 Stock option awards exercised − (251 ) 3.75 Stock option awards cancelled 701 (701 ) 6.82 Balance at December 31, 2019 968 21,050 5.96 Plan amendment 8,000 − − Restricted stock awards granted (31 ) − − Stock option awards granted (7,469 ) 7,469 8.06 Stock option awards exercised − (510 ) 3.56 Stock option awards cancelled 3,124 (3,124 ) 6.93 Balance at December 31, 2020 4,592 24,885 $ 6.52 Weighted Average Awards Options Exercise Available Outstanding Price Balance at December 31, 2019 171 1,329 $ 3.60 Plan amendment 2,900 − − Stock option awards granted (3,002 ) 3,002 4.02 Stock option awards cancelled 160 (160 ) 4.15 Balance at December 31, 2020 229 4,171 $ 3.88
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	20 20 201 9 201 8 Expected Life 5.5 5.5 5.5 Expected Volatility 84 % 81 % 82 % Expected Dividend Yield 0.0 % 0.0 % 0.0 % Risk-Free Interest Rate 0.4 % 1.8 % 2.7 %
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable [Table Text Block]	Outstanding Exercisable Weighted Weighted Weighted Average Average Average Remaining Exercise Exercise Range Number Life Price Number Price $ 0 to 3 2,514 6.1 $ 2.19 1,414 $ 1.25 3 to 6 12,689 7.0 4.22 6,854 2.48 6 to 9 10,852 9.2 7.88 2,005 4.89 9 to 12 2,347 4.5 10.85 2,129 4.51 12 to 15 559 4.1 12.30 539 6.43 15 to 18 95 4.5 15.39 95 10.57 $ 0 to 18 29,056 7.5 $ 6.14 13,036 $ 3.27
Share-based Payment Arrangement, Option, Activity [Table Text Block]	Non-Vested Stock Option Awards Weighted Average Grant-Date Fair Value Balance December 31, 2019 11,688 $ 3.77 Stock option awards granted 10,471 4.69 Stock option awards vested (4,543 ) 4.12 Stock option awards forfeited (1,596 ) 3.96 Balance December 31, 2020 16,020 $ 4.25

Note 9 - Income Taxes (Tables)

Note 9 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	2020 Domestic $ (176,613 ) Foreign (6,201 ) Loss before provision for income taxes $ (182,814 )
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	20 20 201 9 201 8 Income tax benefit at federal statutory rate ( 21% $ (38,391 ) $ (22,868 ) $ (21,263 ) State and local income taxes net of federal tax benefit (2,544 ) (1,591 ) (2,547 ) Permanent items 774 691 503 Rate change (82 ) 625 (29 ) Expiration of attribute carryforwards 3,774 3,976 2,183 Research and development tax credits (4,080 ) (4,938 ) (4,905 ) Foreign rate differential 542 - - Other 1,456 281 18 Change in valuation allowance 38,551 23,824 26,040 Income tax expense $ - $ - $ -
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]	20 20 201 9 Balance at January 1, $ 7,210 $ 5,976 Additions to current period tax positions 1,020 1,234 Additions to prior period tax positions − − Reductions to prior period tax provisions − − Balance at December 31, $ 8,230 $ 7,210
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	20 20 201 9 Deferred tax assets: Net federal and state operating losses $ 159,939 $ 155,190 Research and development credits 66,331 63,275 Royalty income 28,034 - Stock-based compensation 10,732 9,786 Leasing obligations 1,135 1,070 Other 5,563 3,801 Total deferred tax assets 271,734 233,122 Deferred tax liabilities: Fixed assets (124 ) (114 ) Right of use asset (854 ) (803 ) Total deferred tax liabilities (978 ) (917 ) Valuation allowance (270,756 ) (232,205 ) Net deferred tax assets $ − $ −

Note 12 - Quarterly Financial_2

Note 12 - Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Notes Tables
Quarterly Financial Information [Table Text Block]	First Second Third Fourth 20 20 Quarters Revenues $ 4,823 $ 2,871 $ 6,102 $ 4,016 Net Loss (37,599 ) (38,607 ) (46,115 ) (60,493 ) Basic and diluted net loss per share (0.24 ) (0.24 ) (0.26 ) (0.34 ) 2019 Quarters Revenues $ 5,887 $ 1,448 $ 1,775 $ 39,725 Net Loss (31,054 ) (37,629 ) (37,592 ) (2,622 ) Basic and diluted net loss per share (0.28 ) (0.34 ) (0.34 ) (0.02 )

Note 1 - Significant Accounti_3

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

Note 1 - Significant Accounti_4

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

Note 1 - Significant Accounti_5

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

Note 1 - Significant Accounti_6

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

Note 1 - Significant Accounti_7

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

Note 2 - Property and Equipme_3

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

Note 2 - Property and Equipme_4

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

Note 3 - Royalty Monetizations

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

Note 4 - Credit Agreement (Deta

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

Note 5 - Senior Credit Facili_2

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

Note 6 - Lease Obligations an_3

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

Note 6 - Lease Obligations an_4

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

Note 7 - Stockholders' Equity (

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

Note 8 - Stock-based Compensa_3

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

Note 8 - Stock-Based Compensa_4

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

Note 8 - Stock-based Compensa_5

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

Note 8 - Stock-based Compensa_6

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

Note 8 - Stock-based Compensa_7

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

Note 8 - Stock-based Compensa_8

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

Note 9 - Income Taxes (Details

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

Note 9 - Income Taxes - Loss Be

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

Note 9 - Income Taxes - Differe

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

Note 9 - Income Taxes - Diffe_2

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

Note 9 - Income Taxes - Reconci

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

Note 9 - Income Taxes - Compone

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

Note 10 - Employee 401(k) Plan

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

Note 11 - Collaborative and O_2

Note 11 - Collaborative and Other Research and Development Contracts (Details Textual) - USD ($) $ in Thousands

Sep. 03, 2020

Mar. 04, 2020

Nov. 05, 2019

Sep. 06, 2018

Jun. 16, 2015

Aug. 31, 2020

Jun. 30, 2006

Jun. 30, 2000

Dec. 31, 2020

Sep. 30, 2020

Jun. 30, 2020

Mar. 31, 2020

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Jun. 30, 2020

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2020

Dec. 31, 2020

Mar. 31, 2015

Nov. 11, 2011

Revenue from Contract with Customer, Including Assessed Tax

$ 4,016

$ 6,102

$ 2,871

$ 4,823

$ 39,725

$ 1,775

$ 1,448

$ 5,887

$ 17,812

$ 48,835

$ 20,653

Arbitration Proceedings of SUL Agreement [Member]

Litigation Settlement, Amount Awarded from Other Party

$ 5,000

Arbitration Proceedings of SUL Agreement [Member] | Other Income [Member]

Gain (Loss) Related to Litigation Settlement, Total

8,893

Arbitration Proceedings of SUL Agreement [Member] | Selling, General and Administrative Expenses [Member]

Legal Fees

$ 5,026

US Department of Health and Human Services [Member]

Collaborative Agreement Contract Value

$ 34,660

Contract Term (Year)

5 years

Proceeds from Collaborators

$ 6,932

13,864

Torii Pharmaceutical Co. [Member]

Upfront Payments Receivable Amount

$ 22,000

Potential Milestone Payments Receivable if Regulatory Approval Before December 31, 2021

$ 15,000

Maximum Customary Reduction on Royalty Rate

50.00%

Royalty Payments Receivable, Expiration Term From First Commercial (Year)

10 years

Revenue from Contract with Customer, Including Assessed Tax

20,101

Contract with Customer, Liability, Revenue Recognized

1,899

Torii Pharmaceutical Co. [Member] | License [Member]

Revenue from Contract with Customer, Including Assessed Tax

$ 19,344

Torii Pharmaceutical Co. [Member] | Service [Member]

Revenue from Contract with Customer, Including Assessed Tax

757

Torii Pharmaceutical Co. [Member] | Minimum [Member]

Royalty Rate if Maintains Sakigake Designation

20.00%

Torii Pharmaceutical Co. [Member] | Maximum [Member]

Royalty Rate if Maintains Sakigake Designation

40.00%

CSL Limited [Member

Proceeds from License Fees Received

$ 33,740

Milestone Payment Received

$ 12,000

Base Contract [Member]

Government Contract Receivable

$ 16,265

Additional Development Options [Member]

Government Contract Receivable

22,855

ASPRBARDA Contract [Member]

Government Contract Receivable

$ 39,120

Proceeds from awards for Research and Development Contracts

$ 20,574

Green Cross Corporation [Member]

Proceeds from License Fees Received

$ 250

Mundipharma [Member]

Potential Milestone Payments Receivable

$ 15,000

AECOM and IRL [Member]

Milestone Payment Minimum

$ 1,400

Milestone Payment Maximum

4,000

Annual License Fee Minimum

150

Annual License Fee Maximum

$ 500

National Institute of Allergy and Infectious Diseases [Member]

Expected Receivable From Awards for Research and Development Contracts

$ 45,931

Collaborative Agreement Contract, Covenant, Maximum Amount of Funding

$ 43,908

Collaborative Agreement Contract Value

$ 6,326

UAB [Member]

Period of Agreement (Year)

25 years

Renewable Period of Agreement (Year)

5 years

Note 12 - Quarterly Financial_3

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