Stockholders' Equity - Additional Information (Detail) (USD $)	0 Months Ended					6 Months Ended		12 Months Ended
	Nov. 20, 2012	Nov. 20, 2012	Jul. 05, 2012	Jul. 05, 2012	Feb. 21, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2011
Stockholders' Equity
Shares of common stock, authorized (shares)								600,000,000	600,000,000
Shares of common stock, issued and sold (shares)								140,354,605	126,367,700
Gross proceeds in a private placement					$ 17,900,000	$ 0	$ 0	$ 0	$ 17,848,000	$ 0
Shares sold in private placement by founder (shares)					700,000
Shares Issued Under Initial Public Offer Offering Price Per Share	$ 28.00	$ 28.00	$ 18.00	$ 18.00
Issuance of common stock upon follow-on offering, net of issuance costs (in shares)	16,100,000
Issuance of common stock upon initial public offering, net of offering costs (in shares)			13,397,500
Net proceeds from initial public offering			173,300,000			0	0	0	169,784,000	0
Issuance costs		1,200,000		3,500,000
Net proceeds from (offering costs paid in connection with) follow-on offering	51,000,000							56,498,000	49,850,000
Price per share (usd per share)								$ 56.01
Common stock issued under employee stock plans (in shares)								12,951,123	6,654,558
Common Stock, Shares, Outstanding								140,354,605	126,367,700
Preferred Stock, Shares Authorized								10,000,000	10,000,000
Preferred Stock, Shares Outstanding			10,462,877	10,462,877				0	0
Private Placement [Member]
Stockholders' Equity
Shares of common stock, issued and sold (shares)					1,750,980
Common stock issued and sold, (usd per share)					$ 10.20
10 Dollar per share [Member]
Stockholders' Equity
Repurchase and cancellation of common shares (shares)									100,000
11 Dollar per share [Member]
Stockholders' Equity
Repurchase and cancellation of common shares (shares)									77,498
12 Dollar Per Share [Member]
Stockholders' Equity
Repurchase and cancellation of common shares (shares)									6,666
One Lac Shares [Member]
Stockholders' Equity
Price per share (usd per share)									$ 10
77498 Shares [Member]
Stockholders' Equity
Price per share (usd per share)									$ 11.5
6666 Shares [Member]
Stockholders' Equity
Price per share (usd per share)									$ 12.00
Parent [Member]
Stockholders' Equity
Issuance of common stock upon follow-on offering, net of issuance costs (in shares)	1,897,500
Issuance of common stock upon initial public offering, net of offering costs (in shares)			10,350,000
Stock issued under underwriters exercise of over allotment option (shares)	247,500		1,350,000
Founder [Member]
Stockholders' Equity
Issuance of common stock upon initial public offering, net of offering costs (in shares)			3,047,500
Stock issued under underwriters exercise of over allotment option (shares)			397,500
Investor [Member]
Stockholders' Equity
Issuance of common stock upon follow-on offering, net of issuance costs (in shares)	14,202,500
Stock issued under underwriters exercise of over allotment option (shares)	1,852,500
Common Stock
Stockholders' Equity
Conversion of preferred stock to common stock upon initial public offering (in shares)									83,703,016
Issuance of common stock upon follow-on offering, net of issuance costs (in shares)									1,897,500
Issuance of common stock upon initial public offering, net of offering costs (in shares)									10,350,000
Net proceeds from (offering costs paid in connection with) follow-on offering								$ 14,000
Repurchase and cancellation of common shares (shares)						(12,084)			184,164
Common stock issued under employee stock plans (in shares)								13,986,905
Common stock issued under employee stock plans (in shares)						1,469,118			6,654,558	4,279,456