Stock-Based Awards and Stock-Based Compensation - Additional Information (Detail)		1 Months Ended	12 Months Ended
	Jan. 01, 2016 shares	May. 31, 2015 USD ($) offering_period purchase_date shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 shares	Dec. 31, 2013 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock instrument, issued in period (shares)		0
Additional shares reserved for future issuance (shares)			2,870,538
Number of options granted (shares)			2,440,695
Options exercisable by non-employees (shares)			4,633,363
Unrecognized stock-based compensation | $			$ 32,900,000
Weighted average remaining vesting period			2 years 10 months 24 days
Employee stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (shares)		2,000,000
Maximum employee contribution (percent)		15.00%
Maximum employee contribution | $		$ 25,000
Maximum employee purchase (shares)		3,000
Offering period		12 months
Duration of offering period		6 months
Number of offering periods per year | purchase_date		2
Duration of offering period for purchases		6 months
Number of available offering periods to participants | offering_period		1
Discount from market price (percent)		85.00%
Stock-based awards to non-employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted (shares)			0	0	0
Options exercisable by non-employees (shares)			0
2011 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted options vesting period			4 years
Increase in number of shares available for issuance (shares)			5,000,000
Increase in shares available for grant as a percent of total shares outstanding (percent)			3.90%
Share-based payment award, description			The 2011 Plan increases on the first day of each year in an amount equal to the lesser of (i) 5,000,000 shares; (ii) 3.9% of the outstanding shares on the last day of the immediately preceding year; or (iii) such number of shares as determined by the board of directors.
2011 Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted options expiration period			10 years
2011 Plan [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares reserved for future issuance (shares)	2,979,417
2011 Plan [Member] | Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted options vesting period			1 year
2011 Plan [Member] | Performance stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted options vesting period			4 years