Balance Sheet Information - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Payroll, bonuses, and other employee benefits	$ 1,263	$ 2,029
Paid time off	1,242	1,230
Inventory receipts	1,163	1,622
Warranties	420	394
Income and sales taxes	410	546
Professional fees and contractors	191	320
Real estate taxes	190	152
Customer prepayments	129	164
Employee stock purchase plan	124	300
Deferred revenues	93	104
Restructuring	77	126
Other	319	190
Total	$ 5,621	$ 7,177