Stockholders' Equity - Summary of Stock Option Activity (Detail) - Stock Option $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Number of Shares, Beginning balance (in shares) | shares	861,366
Granted, Number of Shares (in shares) | shares	1,670,000
Canceled, Number of Shares (in shares) | shares	(49,824)
Outstanding, Number of Shares, Ending balance (in shares) | shares	2,481,542
Exercisable, Number of Shares (in shares) | shares	432,542
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding, Weighted-Average Exercise Price, Beginning balance (in dollars per share) | $ / shares	$ 3.99
Granted, Weighted-Average Exercise Price (in dollars per share) | $ / shares	4.35
Canceled, Weighted-Average Exercise Price (in dollars per share) | $ / shares	5.68
Outstanding, Weighted-Average Exercise Price, Ending balance (in dollars per share) | $ / shares	4.22
Exercisable, Weighted-Average Exercise Price (in dollars per share) | $ / shares	$ 5.28
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures
Outstanding, Aggregate Intrinsic Value | $	$ 1,759
Exercisable, Aggregate Intrinsic Value | $	$ 315
Outstanding, Weighted-Average Remaining Contractual Term (in years)	8 years 5 months 5 days
Exercisable, Weighted-Average Remaining Contractual Life (in years)	1 year 11 months 19 days