Commitments and Contingencies - Additional Information (Detail)	1 Months Ended	3 Months Ended		6 Months Ended
	Nov. 30, 2017 USD ($) ft²	Mar. 31, 2018 USD ($) € / $	Mar. 31, 2017 USD ($)	Mar. 31, 2018 USD ($) € / $	Mar. 31, 2018 EUR (€)	Mar. 31, 2017 USD ($)
Commitments And Contingencies [Line Items]
License agreement commencement date				2006-03	2006-03
Annual minimum payments for licenses				$ 246,000	€ 200,000
Exchange rate relating to license payment | € / $		1.2319		1.2319
Future minimum payments associated with license		$ 2,500,000		$ 2,500,000
Rent expense related to operating leases		100,000	$ 100,000	200,000		$ 200,000
Amount deposited into restricted cash account		350,000		350,000
Eden Prairie Minnesota [Member]
Commitments And Contingencies [Line Items]
Square feet facility | ft²	36,000
Contractual obligations	$ 4,000,000
Operating lease agreement term	10 years
Operating lease agreement expected commencement date	2018-05
Amount deposited into restricted cash account	$ 400,000
Capitalized leasehold improvements in progress included in property and equipment		2,000		$ 2,000
Patents [Member]
Commitments And Contingencies [Line Items]
Patent expiry date				2027-09	2027-09
Selling, general and administrative [Member]
Commitments And Contingencies [Line Items]
Claim accrual recorded in selling, general and other administrative expenses		1,000,000
Other Accrued Liabilities [Member]
Commitments And Contingencies [Line Items]
Claim accrual recorded in other accrued liabilities		$ 1,000,000		$ 1,000,000