Note 4 - Balance Sheet Components (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Accounts Receivable, after Allowance for Credit Loss	$ 1,088,000.000		$ 1,088,000.000
Accounts Receivable, Allowance for Credit Loss	0		0		$ 0
Unbilled Receivables, Current	3,689,000		3,689,000		0
Depreciation	900,000	$ 900,000	1,800,000	$ 1,800,000
Tangible Asset Impairment Charges	0	0	0	0
Operating Lease, Right-of-Use Asset	22,652,000		22,652,000		24,840,000
Amortization of Intangible Assets	200,000	$ 200,000	400,000	$ 400,000
Goodwill	4,508,000		4,508,000		4,508,000
Goodwill, Impairment Loss			$ 0
Developed Technology Rights [Member]
Finite-Lived Intangible Asset, Remaining Life (Year)			5 years 4 months 24 days
Intellectual Property [Member]
Finite-Lived Intangible Asset, Remaining Life (Year)			3 years 6 months
Facility in Burlingame, California [Member]
Operating Lease, Right-of-Use Asset					3,100,000
BARDA [Member]
Unbilled Receivables, Current	3,700,000		$ 3,700,000		0
Government Contract [Member]
Accounts Receivable, after Allowance for Credit Loss	1,053,000.000		1,053,000.000
Royalty [Member]
Accounts Receivable, after Allowance for Credit Loss					$ 3,000,000
Prepaid Royalties	$ 35,000		$ 35,000