Quarterly report pursuant to Section 13 or 15(d)

Related-Party Transactions - Additional Information (Details)

v3.20.1
Related-Party Transactions - Additional Information (Details) - USD ($)
12 Months Ended
Mar. 30, 2020
Dec. 31, 2019
Mar. 31, 2020
Related Party Transaction [Line Items]      
Receivable from agreement   $ 6,298,000 $ 9,079,000
Merck | Sutro Biopharma      
Related Party Transaction [Line Items]      
Equity interest percentage   11.80% 11.70%
SutroVax      
Related Party Transaction [Line Items]      
Receivable from agreement   $ 14,000 $ 49,000
Percentage common stock ownership interest 4.10% 5.60%  
Carrying value of common stock under the cost method $ 0 $ 0