Note 9 - Leases (Details Textual)
12 Months Ended
Mar. 26, 2021
USD ($)
Dec. 12, 2012
USD ($)
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
ft²
Dec. 31, 2020
USD ($)
Apr. 30, 2021
USD ($)
Apr. 21, 2021
Gain (Loss) on Termination of Lease $ 500,000     $ 522,000 $ (0)    
Operating Lease, Right-of-Use Asset       $ 4,302,000 $ 3,150,000 [1]    
Lessee, Operating Lease, Renewal Term (Year)   2 years          
Lessee, Operating Lease, Notice Period (Year)   18 years          
Lessee, Operating Lease, Annual Overhead Fee Payments   $ 200,000          
Catalent Pharma Solutions [Member]              
Lessee, Operating Lease, Term of Contract (Year)             5 years
Lessee, Operating Lease, Renewal Term (Year)             2 years
Catalent Pharma Solutions [Member] | Forecast [Member]              
Operating Lease, Expense     $ 1,000,000.0        
Prepaid Expenses and Other Current Assets [Member]              
Lessee, Operating Sublease, Deferred Costs           $ 300,000  
Lease for Corporate Headquarters in Hayward, California [Member]              
Area of Real Estate Property (Square Foot) | ft²       12,106      
Lessee, Operating Lease, Term of Contract (Year) 2 years 3 months            
Lessee, Operating Lease, Monthly Rent $ 17,000            
Lessee, Operating Lease, Abated Rent Period (Month) 1 month            
Operating Lease, Right-of-Use Asset $ 400,000            
[1] The condensed consolidated balance sheet as of December 31, 2020 has been derived from the audited financial statements as of that date included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020.