Capital Stock - Reserved Shares of Common Stock (Detail)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity [Abstract]
Issuance in connection with outstanding stock options	2,244,363	1,675,506	1,989,237	2,871,005
Issuance in connection with restricted stock units outstanding	2,279,081	1,044,651	446,915
Reserved for future stock option and restricted stock unit grants	1,166,742	1,847,752
Reserved for future issuance under the employee stock purchase plan	895,268	831,271
Total	6,585,454	5,399,180