Significant Accounting Policies - Summary of Percentage of Total Product Revenues (Details) - Revenue from Contract with Customer Benchmark - Customer Concentration Risk	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
OncoMed Specialty, LLC (Onco360)
Disaggregation Of Revenue [Line Items]
Percentage of product revenues	22.00%	0.00%	0.00%
Affiliates of McKesson Corporation
Disaggregation Of Revenue [Line Items]
Percentage of product revenues	42.00%	0.00%	0.00%
Affiliates of AmerisourceBergen Corporation
Disaggregation Of Revenue [Line Items]
Percentage of product revenues	27.00%	0.00%	0.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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