Stock Incentive Plans - Summary of Options, RSUs Activity under 2014 Equity Incentive Plan and 2016 Inducement Plan and Related Information (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Shares Available for Grant
Beginning balance (in shares)	322,178
Additional options authorized (in shares)	1,855,398
Common stock awards for services (in shares)	(7,569)
Options granted (in shares)	(991,130)
Repurchases of common stock under employee incentive plans (in shares)	142,103
RSUs forfeited (in shares)	187,229
Options forfeited (in shares)	241,533
Options expired (in shares)	15,121
Ending balance (in shares)	504,775	322,178
RSUs forfeited (in shares)	(187,229)
Stock Options Outstanding
Beginning balance (in shares)	2,501,057
Options granted (in shares)	991,130
Options exercised (in shares)	(625,685)
Options forfeited (in shares)	(241,533)
Options expired (in shares)	(15,121)
Ending balance (in shares)	2,609,848	2,501,057
Weighted average exercise price, outstanding (in dollars per share)	$ 16.47	$ 9.10
Options granted, weighted average exercise price (in dollars per share)	27.88
Options exercised, weighted average exercise price (in dollars per share)	5.70
Options forfeited, weighted-average exercise price (in dollars per share)	15.37
Options expired, weighted-average exercise price (in dollars per share)	$ 6.45
Restricted stock units
Shares Available for Grant
Granted (in shares)	(1,260,088)
RSUs forfeited (in shares)	187,229
RSUs, beginning balance (in shares)	968,364
Granted (in shares)	1,260,088
Vested (in shares)	(524,938)
RSUs forfeited (in shares)	(187,229)
RSUs, ending balance (in shares)	1,516,285	968,364
Stock Options Outstanding
Outstanding, weighted-average grant date fair value (in dollars per share)	$ 22.51	$ 11.49
RSUs granted, weighted-average grant date fair value (in dollars per share)	27.27
RSUs vested, weighted-average grant date fair value (in dollars per share)	15.09
RSUs forfeited, weighted-average grant date fair value (in dollars per share)	$ 21.88