Net Income Per Share - Outstanding Dilutive Potential Shares Excluded from Calculation of Diluted Net Income Per Share Attributable to Coherus (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from the calculation of diluted net loss per share	12,748,634	14,815,669	11,384,913	14,669,249
Stock Options, Including Purchases from Contributions to ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from the calculation of diluted net loss per share	12,739,884	10,341,798	11,378,471	10,195,378
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from the calculation of diluted net loss per share	8,750		6,442
Convertible Notes
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from the calculation of diluted net loss per share	0	4,473,871	0	4,473,871