Note F - Common Stock and Warrants (Details Textual) - USD ($) $ / shares in Units, $ in Thousands					1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 26, 2021	Jan. 12, 2021	Oct. 25, 2018	Jun. 02, 2014	Jan. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Jun. 18, 2021	Dec. 31, 2021	Feb. 03, 2021	Jan. 08, 2021	Dec. 31, 2020
Common Stock, Shares Authorized (in shares)						250,000,000			250,000,000
Common Stock, Shares, Issued (in shares)						35,333,450			35,325,801
Common Stock, Shares, Outstanding, Ending Balance (in shares)						34,423,497			35,005,640
Proceeds from Warrant Exercises						$ 0	$ 25,593
Preferred Stock Dividends and Other Adjustments, Total						$ (0)	$ 37,444
Other Noncurrent Assets [Member]
Contract with Customer, Asset, after Allowance for Credit Loss, Total									$ 400
Deerfield Warrant [Member]
Class of Warrant or Right Issued (in shares)				14,423,076
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 46.25							$ 38.34				$ 93.60
Deerfield Warrant [Member] | Common Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)				1,923,077								120,192
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 46.25			$ 5.85				$ 38.34				$ 93.60
Warrant Issued to KVK [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			500,000									31,250
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)			$ 2.30									$ 36.80
Class of Warrant or Right, Additional Shares Exercisable for Each Milestones (in shares)			125,000
Pre-funded Warrants [Member] | Roth Capital Partners, LLC [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		926,844									926,844
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 0.0001
Stock Issued During Period, Shares, Warrant Exercises (in shares)					926,841
Proceeds from Warrant Exercises					$ 72,000
Public Offering Warrants [Member] | Roth Capital Partners, LLC [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		12,078,361									7,692,307
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 6.50									$ 6.50
Stock Issued During Period, Shares, Warrant Exercises (in shares)						3,030,881
Proceeds from Warrant Exercises						$ 16,900
Warrants and Rights Outstanding, Term (Year)		5 years
Maximum Percent of Common Stock Ownership Allowed Per Holder Upon Warrant Exercise		4.99%
Class of Warrants or Right, Exercised During Period (in shares)						3,461,858
Underwriter Warrants [Member] | Roth Capital Partners, LLC [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)		806,932								18,702	754,035
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 8.125
Stock Issued During Period, Shares, Warrant Exercises (in shares)						400,000
Proceeds from Warrant Exercises						$ 3,300
Class of Warrants or Right, Exercised During Period (in shares)						400,000
Over Allotment Options, Percentage of Common Stock Outstanding for Warrants		5.00%
Existing Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	6,620,358
Proceeds from Warrant Exercises	$ 44,000
Placement Agent Fee, Percentage	6.00%
January 2021 Inducement Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	7,944,430							6,117,509
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 6.36
Stock Issued During Period, Shares, Warrant Exercises (in shares)						1,676,921
Proceeds from Warrant Exercises						$ 10,700		$ 39,100
Warrants and Rights Outstanding, Term (Year)	5 years
Maximum Percent of Common Stock Ownership Allowed Per Holder Upon Warrant Exercise	4.99%
Class of Warrants or Right, Exercised During Period (in shares)						1,676,921
Warrants Issued Upon Exchange, Percentage of Shares Issued Upon Exercise	120.00%
Class of Warrant, Purchase Price Per Warrant (in dollars per share)	$ 0.125
Placement Agent Fee, Percentage								6.00%
Maximum Percent of Common Stock Ownership Allowed Per Holder After Warrant Exercise Upon Holders Selection	9.99%
Preferred Stock Dividends and Other Adjustments, Total						$ 37,400
June 2021 Inducement Warrants [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)								1,529,379
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)								$ 16.50
Maximum Percent of Common Stock Ownership Allowed Per Holder Upon Warrant Exercise								4.99%
Class of Warrants or Right, Exercised During Period (in shares)						0
Warrants Issued Upon Exchange, Percentage of Shares Issued Upon Exercise								25.00%
Class of Warrant, Purchase Price Per Warrant (in dollars per share)								$ 0.125
Maximum Percent of Common Stock Ownership Allowed Per Holder After Warrant Exercise Upon Holders Selection								9.99%
Preferred Stock Dividends and Other Adjustments, Total						$ 16,900