Equity Compensation Plans (Detail) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares
Shares
Outstanding at March 31,2017 (shares) | shares	415
Exercisable at March 31, 2017 (shares) | shares	233
Unvested at March 31,2017 (shares) | shares	182
Weighted-Average Exercise Price (usd per share)
Outstanding at March 31, 2017 (in dollars per share) | $ / shares	$ 25.69
Exercisable at March 31, 2017 (in dollars per share) | $ / shares	16.04
Unvested at March 31, 2017 (in dollars per share) | $ / shares	$ 38.00
Weighted- Average Remaining Contractual Term (years)
Outstanding at March 31, 2017	6 years 8 months 12 days
Exercisable at March 31, 2017	5 years 4 months 24 days
Unvested at March 31, 2017	8 years 6 months
Aggregate Intrinsic Value
Outstanding at March 31, 2017 | $	$ 11,988
Exercisable at March 31, 2017 | $	8,738
Unvested at March 31, 2017 | $	$ 3,250