Note C - Debt Obligations (Details Textual) - USD ($)									1 Months Ended	3 Months Ended		9 Months Ended	12 Months Ended
	Feb. 08, 2021	Jan. 12, 2021	Jan. 01, 2021	Apr. 23, 2020	Jan. 13, 2020	Dec. 18, 2019	Feb. 09, 2016	Jun. 02, 2014	Jun. 30, 2018	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2021	Jun. 18, 2021	Jan. 26, 2021	Dec. 31, 2019	Sep. 30, 2019	Sep. 02, 2019	Jun. 30, 2016
Convertible Notes Payable, Total										$ 0				$ 0
Debt Conversion, Converted Instrument, Shares Issued (in shares)												1,777,437
Interest Paid, Excluding Capitalized Interest, Operating Activities										$ 5,000	$ 199,000
Debt Instrument, Convertible, Minimum Conversion Price (in dollars per share)																	$ 9.328
Conversion from Deerfield Convertible Note to Common Stock [Member]
Debt Conversion, Original Debt, Amount									$ 3,300,000
Debt Conversion, Accrued Interest									$ 200,000
Debt Conversion, Converted Instrument, Shares Issued (in shares)									37,410
Conversion of December 2019 Notes into Common Stock [Member]
Debt Conversion, Original Debt, Amount												$ 17,100,000
December 2020 Exchange Agreement [Member]
Debt Conversion, Original Debt, Amount		$ 31,500,000
Debt Conversion, Converted Instrument, Shares Issued (in shares)		31,476.98412
Debt Conversion, Converted Instrument, Warrants or Options Issued (in shares)		3,632,019
Deerfield Convertible Notes [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)																	93.60
2021 Notes [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)							$ 17.11						$ 273.76
Debt Conversion, Original Debt, Amount							$ 1,000						$ 1,000
Debt Conversion, Converted Instrument, Shares Issued (in shares)							58.4454						3.6528
Debt Instrument, Interest Rate, Stated Percentage							5.50%
Debt Instrument, Face Amount							$ 86,300,000
Proceeds from Debt, Net of Issuance Costs							82,800,000
Repayments of Long-term Debt, Total							18,600,000
Debt Instrument, Sinking Fund Payment							$ 0
Debt Instrument Repurchase Price Equal to Percentage of Principal Amount							100.00%
Debt Instrument, Cancellation of Debt, Amount					$ 3,000,000.0	$ 71,400,000
Interest Paid, Excluding Capitalized Interest, Operating Activities					$ 37,000	$ 700,000
Debt Instrument, Percentage of Accrued Interest Paid						50.00%
The 2019 Notes [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)					$ 5.85	$ 17.11							$ 93.60				273.76
Debt Instrument, Interest Rate, Stated Percentage						6.75%
Debt Instrument, Face Amount						$ 71,400,000
Debt Instrument, Percentage of Accrued Interest Paid					50.00%
Debt Instrument, Convertible, Minimum Conversion Price (in dollars per share)					$ 0.583												$ 0.38
Debt Instrument, Convertible, Conversion Restriction Percentage of Common Stock						4.985%
Beneficial Ownership, Cap Limit, Percentage						19.985%
Debt Instrument, Convertible, Floor Price (in dollars per share)													$ 9.328
January 2020 Note [Member]
Debt Instrument, Face Amount					$ 3,000,000.0
The December 2020 Exchange Agreement [Member]
Repayments of Debt			$ 30,300,000
The December 2019 and January 2020 Notes [Member]
Long-term Debt, Gross													$ 60,800,000
Deerfield Facility Agreement [Member]
Long-term Debt, Gross													7,500,000
The Facility Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage		6.75%
Repayments of Long-term Debt, Total		$ 30,300,000
Long-term Debt, Total		$ 7,600,000											$ 69,400,000
Paycheck Protection Program CARES Act [Member]
Proceeds from Issuance of Long-term Debt, Total				$ 800,000
Deerfield Facility Agreement [Member]
Line of Credit Facility, Maximum Borrowing Capacity								$ 60,000,000
Line of Credit Facility, Interest Rate at Period End								9.75%												6.75%
Debt Instrument, Interest Rate, Stated Percentage																		6.75%	9.75%
Convertible Notes Payable, Current											$ 7,000,000.0
Debt Covenant, Debt Financing Restriction								$ 750,000
Repayments of Long-term Debt, Total	$ 8,000,000.0
Debt Instrument, Convertible, Minimum Conversion Price (in dollars per share)						$ 0.60
Conversion of Stock, Maximum Shares Issued (in shares)						28,439,015
Debt Instrument, Convertible, Optional Conversion Feature, Exchange Price (in dollars per share)													$ 9.60
Debt Instrument, Convertible Optional Conversion Feature Shares Issuable Upon Exchange (in shares)													1,777,437
Deerfield Facility Agreement [Member] | Deerfield Warrant [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)								$ 0.78
Deerfield Facility Agreement [Member] | Deerfield Warrant [Member] | IPO [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)								1,923,077
Deerfield Facility Agreement [Member] | Series D Redeemable Convertible Preferred Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)								14,423,076
Deerfield Facility Agreement [Member] | Term Notes [Member]
Proceeds from Secured Notes Payable								$ 15,000,000
Deerfield Facility Agreement [Member] | Deerfield Convertible Notes [Member]
Proceeds from Secured Notes Payable								$ 10,000,000
Debt Instrument, Convertible, Conversion Price (in dollars per share)								$ 5.85					$ 93.60
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)													120,192
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)								$ 5.85					$ 93.60		$ 38.34	$ 46.25