Summary of Significant Accounting Policies - Schedule of Deferred Revenue Balance (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 5,624	$ 4,877
Regional Growth Fund [Member]
Deferred Revenue Arrangement [Line Items]
Deferred revenue	592	1,480
Product Revenues [Member]
Deferred Revenue Arrangement [Line Items]
Deferred revenue	4,647	2,854
Service Revenues [Member]
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 385	$ 543