Commitments and Contingencies - Additional Information (Detail) - Mar. 31, 2020 $ in Millions	USD ($)	GBP (£)
Commitments And Contingencies Disclosure [Line Items]
Potential payable amount over the agreement terms based on minimum purchase obligation	$ 167.2
Further Indication for AMR101 | Marketing Approval In Europe
Commitments And Contingencies Disclosure [Line Items]
Potential aggregate stock or cash payment	9.3	£ 7,500,000
Further Indication for AMR101 | Potential Marketing Approval 1
Commitments And Contingencies Disclosure [Line Items]
Potential aggregate stock or cash payment	6.2	5,000,000
Further Indication for AMR101 | Potential Marketing Approval 2
Commitments And Contingencies Disclosure [Line Items]
Potential aggregate stock or cash payment	$ 6.2	£ 5,000,000