Significant Accounting Policies - Summary of Fair Value, Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Sep. 30, 2019
Business Combination, Contingent Consideration, Liability	$ (19,774)
Derivative Liability, Noncurrent	(703)
Interest Rate Swap [Member]
Derivative Liability, Noncurrent	(703)
Fair Value, Recurring [Member]
Government Grant Obligations	(11,173)	$ 0
Fair Value, Recurring [Member] | Interest Rate Swap [Member]
Derivative Liability, Noncurrent	(703)	0
Fair Value, Recurring [Member] | Commitments [Member]
Business Combination, Contingent Consideration, Liability	(19,774)	(27,202)
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Government Grant Obligations	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Interest Rate Swap [Member]
Derivative Liability, Noncurrent	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commitments [Member]
Business Combination, Contingent Consideration, Liability	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Government Grant Obligations	(11,173)	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]
Derivative Liability, Noncurrent	(703)	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commitments [Member]
Business Combination, Contingent Consideration, Liability	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Government Grant Obligations	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest Rate Swap [Member]
Derivative Liability, Noncurrent	0	0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commitments [Member]
Business Combination, Contingent Consideration, Liability	$ (19,774)	$ (27,202)