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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Summary of Significant Accounting Policies - Concentrations of Credit Risk (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable \| Credit Concentration Risk \| AbbVie
Concentrations
Concentration risk percentage (as a percent)	76.00%	90.00%
Accounts Receivable \| Credit Concentration Risk \| Astellas Pharma Inc.
Concentrations
Concentration risk percentage (as a percent)	1.00%	8.00%
Revenue from Contract with Customer Benchmark \| Customer Concentration Risk \| AbbVie
Concentrations
Concentration risk percentage (as a percent)	96.00%	78.00%	77.00%
Revenue from Contract with Customer Benchmark \| Customer Concentration Risk \| Astellas Pharma Inc.
Concentrations
Concentration risk percentage (as a percent)	1.00%	13.00%	20.00%