Share Based Payments - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares subject to outstanding awards under the plan	3,214,000	3,256,000
Vesting period	4 years
Contractual term	10 years
Treasury stock coupon rate	0.00%
2014 Equity Incentive Plan [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Issuance of common stock	2,500,000
Shares subject to outstanding awards under the plan	1,400,000
Shares available for grant under the plan	1,300,000
2014 Equity Incentive Plan [Member] | Maximum [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Additional number of shares of common stock available for issuance	1,000,000
2005 Stock Plan [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares subject to outstanding awards under the plan	1,800,000
Employee Stock Purchase Plan [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Common stock at a discount	15.00%
Employee stock purchase plan option period, description	Option periods under the ESPP run from January 1 to June 30 and July 1 to December 31 of each year.