Summary of Significant Accounting Policies and Select Balance Sheet Information - Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Property, Plant and Equipment [Line Items]
Less accumulated depreciation	$ (33,512)	$ (29,927)
Property and equipment, net	30,143	22,942
Land [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	4,420	4,420
Laboratory Fixtures and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 22,024	19,491
Laboratory Fixtures and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Useful Life	3 years
Laboratory Fixtures and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Useful Life	10 years
Building and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 21,717	21,924
Building and Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Useful Life	3 years
Building and Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Useful Life	20 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Useful Life	10 years
Property and Equipment, Gross	$ 4,836
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 5,824	4,541
Office Furniture and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Useful Life	3 years
Office Furniture and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Useful Life	10 years
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 4,834	$ 2,493