Annual report pursuant to Section 13 and 15(d)

Related-Party Transactions - Additional Information (Details)

v3.20.1
Related-Party Transactions - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Related Party Transaction [Line Items]      
Revenue from related parties $ 22,536,000 $ 18,966,000 $ 44,606,000
Receivables from agreement 6,298,000 2,489,000  
Celgene      
Related Party Transaction [Line Items]      
Revenue from related parties 8,900,000    
SutroVax      
Related Party Transaction [Line Items]      
Receivables from agreement $ 14,000 $ 49,000  
Percentage common stock ownership interest 5.60% 5.60%  
Carrying value of common stock under the cost method $ 0 $ 0  
Sutro Biopharma | Celgene | Minimum | IPO      
Related Party Transaction [Line Items]      
Equity interest percentage 10.00%    
Sutro Biopharma | Celgene | Maximum [Member] | IPO      
Related Party Transaction [Line Items]      
Equity interest percentage 10.00%    
Sutro Biopharma | Merck      
Related Party Transaction [Line Items]      
Equity interest percentage 11.80% 11.90%