Note 4 - Balance Sheet Components (Details Textual) $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2025 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2024 USD ($)
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions	7			5
Interest Receivable	$ 200			$ 200
Accounts Receivable, after Allowance for Credit Loss	1,500			5,700
Accounts Receivable, Allowance for Credit Loss	0			0
Unbilled Receivables, Current	14,622			6,208
Depreciation	900	$ 900
Tangible Asset Impairment Charges	0		$ 0
Prepaid Expense Other, Noncurrent	60,116			60,116
Operating Lease, Right-of-Use Asset	19,255			20,404
Amortization of Intangible Assets	200	$ 200
Goodwill	4,508			4,508
Goodwill, Impairment Loss	0
Accounts Payable	$ 16,600			$ 7,000
Developed Technology Rights [Member]
Finite-Lived Intangible Asset, Remaining Life (Year)	4 years 7 months 6 days
Intellectual Property [Member]
Finite-Lived Intangible Asset, Remaining Life (Year)	2 years 9 months 18 days
Customer Concentration Risk [Member] | Prepaid Expenses [Member] | Clinical Research Organization [Member]
Concentration Risk, Percentage				28.00%
Customer Concentration Risk [Member] | Accounts Payable [Member] | Clinical Research Organization [Member]
Concentration Risk, Percentage	90.00%			67.00%
Customer Concentration Risk [Member] | Other Accrued Liabilities [Member] | Clinical Research Organization [Member]
Concentration Risk, Percentage	46.00%			42.00%
BARDA [Member]
Unbilled Receivables, Current	$ 14,600			$ 6,200
Government Contract [Member]
Accounts Receivable, after Allowance for Credit Loss				2,700
Royalty [Member]
Prepaid Royalties				$ 3,000