Revenue, Credit Concentrations and Geographic Information - Total Net Product Revenue Concentrations Attributed to Largest Customers (Detail) - Customer Concentration Risk - Net Product Revenue	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Customer A, B, C, & D
Concentration Risk [Line Items]
Concentration risk, percentage	41.00%	48.00%
Customer A
Concentration Risk [Line Items]
Concentration risk, percentage	17.00%	16.00%
Customer B
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%	12.00%
Customer C
Concentration Risk [Line Items]
Concentration risk, percentage	8.00%	9.00%
Customer D
Concentration Risk [Line Items]
Concentration risk, percentage	5.00%	11.00%