Commitments and Contingencies - Additional Information (Detail) $ in Millions		1 Months Ended						6 Months Ended
	Oct. 30, 2017 USD ($)	Feb. 28, 2017 USD ($)	Oct. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Aug. 31, 2016 ft²	May 31, 2016	Sep. 30, 2015 Patent	Sep. 30, 2017
Magnetic Clutch Patents
Commitments and Contingencies [Line Items]
Patents allegedly infringed upon, number | Patent							2
Patent One
Commitments and Contingencies [Line Items]
Patent expiration period						2020-09
Patent Two
Commitments and Contingencies [Line Items]
Patent expiration period						2020-12
Patent Three
Commitments and Contingencies [Line Items]
Patent expiration period						2021-10
Lease Agreements
Commitments and Contingencies [Line Items]
Office space under capital lease | ft²					163,560
Lease agreement termination date					Aug. 31, 2026
Capital lease term								15 years
Lease Agreements | Massachusetts
Commitments and Contingencies [Line Items]
Annual rent expense		$ 0.2
Lease expiration period		2022-07
Lease Agreements | Germany
Commitments and Contingencies [Line Items]
Annual rent expense				$ 0.3
Lease expiration period				2024-05
Lease commencement period				2017-05
Lease Agreements | Japan
Commitments and Contingencies [Line Items]
Annual rent expense			$ 0.9
Lease expiration period			2021-09
Lease Agreements | Subsequent Event
Commitments and Contingencies [Line Items]
Headquarters acquisition	$ 16.5