Significant Accounting Policies - Summary of Percentage of Total Product Revenues (Details) - Revenue from Contract with Customer Benchmark - Customer Concentration Risk	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Percentage of product revenues	100.00%	100.00%
Affiliates of McKesson Corporation
Disaggregation Of Revenue [Line Items]
Percentage of product revenues	42.00%	33.00%
Affiliates of AmerisourceBergen Corporation
Disaggregation Of Revenue [Line Items]
Percentage of product revenues	28.00%	23.00%
OncoMed Specialty, LLC (Onco360)
Disaggregation Of Revenue [Line Items]
Percentage of product revenues	23.00%	31.00%
Affiliates of Cardinal Health Specialty
Disaggregation Of Revenue [Line Items]
Percentage of product revenues	7.00%	13.00%