Stock Incentive Plans - Summary of Option Activity and Related Information (Detail) - 2014 Equity Incentive Plan [Member]	6 Months Ended
	Jun. 30, 2016 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Underlying Stock Options Outstanding, Beginning Balance | shares	1,577,317
Shares Underlying Stock Options Outstanding, Granted | shares	474,045
Shares Underlying Stock Options Outstanding, Exercised | shares	(2,770)
Shares Underlying Stock Options Outstanding, Forfeited | shares	(205,049)
Shares Underlying Stock Options Outstanding, Expired | shares	(1,433)
Shares Underlying Stock Options Outstanding, Ending Balance | shares	1,842,110
Weighted-average Exercise Price, Beginning Balance | $ / shares	$ 6.87
Weighted-average Exercise Price, Granted | $ / shares	5.01
Weighted-average Exercise Price, Exercised | $ / shares	3.14
Weighted-average Exercise Price, Forfeited | $ / shares	6.94
Weighted-average Exercise Price, Expired | $ / shares	11.59
Weighted-average Exercise Price, Ending Balance | $ / shares	$ 6.38