Note 1 - Nature of the Business and Operations and Liquidity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2024	Mar. 31, 2023	Jan. 31, 2024
Retained Earnings (Accumulated Deficit)	$ (1,066,658)	$ (1,066,658)	$ (1,055,547)
Cash, Cash Equivalents, and Marketable Securities	90,500	90,500
Net Cash Provided by (Used in) Operating Activities		$ 2,138	(22,485)
Shelf Registration, Maximum Amount to be Sold				$ 250,000
Restructuring and Related Cost, Number of Positions Eliminated, Period Percent		5.00%
Restructuring and Related Cost, Expected Cost	1,000	$ 1,000
Payments for Restructuring		1,000	$ 331
Restructuring and Related Cost, Expected Annual Savings	$ 5,000	$ 5,000
Public Offering 2024 [Member]
Stock Issued During Period, Shares, New Issues (in shares)	6,210,000
Shares Issued, Price Per Share (in dollars per share)	$ 11.25	$ 11.25
Proceeds from Issuance of Common Stock	$ 65,200