Restatement of the Consolidated Financial Statements - Schedule of Effect of Restatement on Company's Company's Consolidated Statements of Operations, Consolidated Statements of Comprehensive Income (Loss) and Consolidated Statements of Cash Flows (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Product revenues	$ 6,325	$ 5,585
Total revenues	10,477	9,036
Gross profit	4,127	4,158
Research and development	2,133	1,384
Total operating expenses	5,865	4,279
Income (loss) from operations	(1,738)	(121)
Income (loss) before taxes	(1,639)	23
Net income (loss)	$ (1,643)	$ 18
Basis net income (loss) per share	$ (0.15)	$ 0.00
Diluted net income (loss) per share	$ (0.15)	$ 0.00
Net income (loss)	$ (1,643)	$ 18
Comprehensive loss	(2,307)	(969)
Net income (loss)	(1,643)	18
Prepaid expenses and other current assets	(406)	(564)
Accrued expenses	(1,287)	331
Deferred revenue	1,349	(901)
As Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Product revenues	7,949	4,875
Total revenues	12,101	8,326
Gross profit	5,751	3,448
Research and development	1,752
Total operating expenses	5,484
Income (loss) from operations	267	(831)
Income (loss) before taxes	366	(687)
Net income (loss)	$ 362	$ (692)
Basis net income (loss) per share	$ 0.03	$ (0.06)
Diluted net income (loss) per share	$ 0.03	$ (0.06)
Net income (loss)	$ 362	$ (692)
Comprehensive loss	(302)	(1,679)
Net income (loss)	362	(692)
Prepaid expenses and other current assets	(1,152)
Accrued expenses	(922)
Deferred revenue	(275)	(191)
Restatement Adjustments [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Product revenues	(1,624)	710
Total revenues	(1,624)	710
Gross profit	(1,624)	710
Research and development	381
Total operating expenses	381
Income (loss) from operations	(2,005)	710
Income (loss) before taxes	(2,005)	710
Net income (loss)	$ (2,005)	$ 710
Basis net income (loss) per share	$ (0.18)	$ 0.06
Diluted net income (loss) per share	$ (0.18)	$ 0.06
Net income (loss)	$ (2,005)	$ 710
Comprehensive loss	(2,005)	710
Net income (loss)	(2,005)	710
Prepaid expenses and other current assets	746
Accrued expenses	(365)
Deferred revenue	$ 1,624	$ (710)