Note 1 - Nature of the Business and Operations and Liquidity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended	6 Months Ended
	Sep. 23, 2024	Aug. 01, 2024	Jan. 31, 2024	Sep. 30, 2024	Sep. 30, 2024	Sep. 30, 2023	Mar. 31, 2024
Retained Earnings (Accumulated Deficit)				$ (1,064,295)	$ (1,064,295)		$ (1,066,658)
Cash, Cash Equivalents, and Marketable Securities				72,100	72,100
Net Cash Provided by (Used in) Operating Activities					16,121	$ (1,348)
Shelf Registration, Maximum Amount to be Sold			$ 250,000
Shelf Registration, Amount Available for Future Offerings				250,000	250,000
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 1
Megatran [Member]
Business Combination, Consideration Transferred		$ 61,400
Business Combination, Maximum Adjustment Before Indebtedness		25,000
Business Combination, Share Purchase Price Quotient Amount		31,400
Business Combination, Potential Additional Cash Payment		$ 5,000
Payment for Contingent Consideration Liability, Investing Activities	$ 3,300			3,300	3,278	$ (0)
Business Combination, Contingent Consideration Arrangements, Remaining Obligation to Stockholders				$ 0	$ 0
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
Proceeds from Issuance of Common Stock			$ 65,200