Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued in conjunction with the vesting and release of restricted stock units	74,913
Common stock issued due to exercise of stock options	60,511
Common stock issued in connection with employee stock purchase plan	41,162
Employee stock purchase plan, net proceeds	$ 1,600
Repurchase of common stock, shares	1,152,386
Repurchase of common stock	$ 19,600
Shares Paid for Tax Withholding for Share Based Compensation	24,932
Payments Related to Tax Withholding for Share-based Compensation	$ 400
Stock Repurchase Program, Remaining Authorized Repurchase Amount	35,000
Share-based compensation expense recognized	1,980	$ 2,068
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense recognized	1,400	$ 1,400
Total unrecognized compensation expense related to non-vested stock options	$ 8,200
Expected weighted-average period of recognition for unrecognized compensation expense	2 years 11 months
Weighted-average grant date fair value of stock options granted	$ 5.85	$ 9.60
Stock options granted	626,413	544,247
Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense recognized	$ 600	$ 700
Expected weighted-average period of recognition for unrecognized compensation expense	3 years
Total unrecognized compensation expense related to non-vested restricted stock	$ 3,600
Weighted-average grant date fair value of stock options granted	$ 15.39	$ 23.58
Stock options granted	131,972	103,118