Accrued Liabilities - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accrued compensation	$ 904	$ 999
Accrued severance	52	209
Accrued warranty costs	526	384
Accrued legal costs	1,207	915
Accrued SEC civil penalty (Note 12)		1,750
Accrued liabilities, other	1,613	1,432
Accrued liabilities, total	$ 4,302	$ 5,689