Commitments and Contingencies - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2021 GBP (£)	Dec. 31, 2020 USD ($)
Commitments And Contingencies Disclosure [Line Items]
Potential payable amount over the agreement terms based on minimum purchase obligation	$ 213,000
Accrued expenses and other current liabilities	228,734		$ 198,641
Communication costs related to direct-to-consumer activities	14,200
Further Indication for AMR101 | Marketing Approval In Europe
Commitments And Contingencies Disclosure [Line Items]
Potential aggregate stock or cash payment | £		£ 7,500,000
Accrued expenses and other current liabilities	12,000
Further Indication for AMR101 | Potential Marketing Approval 1
Commitments And Contingencies Disclosure [Line Items]
Potential aggregate stock or cash payment	6,900	5,000,000
Further Indication for AMR101 | Potential Marketing Approval 2
Commitments And Contingencies Disclosure [Line Items]
Potential aggregate stock or cash payment	$ 6,900	£ 5,000,000