Equity Awards - Summary of Option Activity and Other Related Information (Detail) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Balance at beginning of period, Options Outstanding | shares	5,109,285
Granted, Options Outstanding | shares	996,769
Exercised, Options Outstanding | shares	(197,136)
Forfeited and expired, Options Outstanding | shares	(176,699)
Balance at end of period, Options Outstanding | shares	5,732,219
Exercisable at end of period, Options Outstanding | shares	2,769,424
Balance at beginning of period, Weighted-Average Exercise Price | $ / shares	$ 8.86
Granted, Weighted-Average Exercise Price | $ / shares	5.76
Exercised, Weighted-Average Exercise Price | $ / shares	7.67
Forfeited and expired, Weighted-Average Exercise Price | $ / shares	14.12
Balance at end of period, Weighted-Average Exercise Price | $ / shares	8.20
Exercisable at end of period, Weighted-Average Exercise Price | $ / shares	$ 8.25
Balance at end of period, Weighted- Average Remaining Term	7 years 10 months 25 days
Exercisable at end of period, Weighted- Average Remaining Term	7 years 1 month 6 days
Balance at end of period, Aggregate Intrinsic Value | $	$ 14,830
Exercisable at end of period, Aggregate Intrinsic Value | $	$ 7,156