Stock-Based Awards and Stock-Based Compensation - Stock Option Activity and Stock Options Outstanding (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, shares available for grant (shares)	3,389,132
Additional shares reserved for future issuance (shares)	2,870,538
Stock options granted, shares available for grant (shares)	(2,440,695)
Forfeited - stock options, shares available for grant (shares)	1,703,380
Vested RSUs adjusted for taxes, shares available for grant (shares)	209,532
Ending balance, shares available for grant (shares)	3,642,166
Beginning balance, Outstanding stock options (shares)	7,329,575
Stock options granted, outstanding stock options (shares)	2,440,695
Forfeited - stock options, outstanding stock options (shares)	(1,703,380)
Stock options exercised, outstanding stock options (shares)	(1,089,933)
Ending balance, outstanding stock options (shares)	6,976,957
Exercisable at December 31, 2015	4,633,363
Vested and expected to vest, outstanding stock options (shares)	6,744,707
Beginning balance, weighted average exercise price (dollars per share) | $ / shares	$ 5.97
Stock options granted, weighted average exercise price (dollars per share) | $ / shares	5.37
Forfeited - stock options, weighted average exercise price (dollars per share) | $ / shares	9.73
Stock options exercised, weighted average exercise price (dollars per share) | $ / shares	1.22
Ending balance, weighted average exercise price (dollars per share) | $ / shares	5.59
Exercisable at December 31, 2014, weighted average exercise price (dollars per share) | $ / shares	5.48
Vested and expected to vest, weighted average exercise price (dollars per share) | $ / shares	$ 5.58
Balances, December 31, 2014, Weighted average remaining life (in years)	5 years 6 months 18 days
Exercisable at December 31, 2014, Weighted average remaining life (in years)	3 years 7 months 24 days
Vested and expected to vest, Weighted average remaining life (in years)	5 years 4 months 20 days
Aggregate intrinsic value, Balances, December 31, 2014 | $	$ 6,878
Aggregate intrinsic value, Exercisable at December 31, 2014 | $	6,876
Aggregate intrinsic value, Vested and expected to vest | $	$ 6,878
Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units granted, shares available for grant (shares)	(3,914,358)
Forfeited, shares available for grant (shares)	1,574,637
Vested RSUs adjusted for taxes, shares available for grant (shares)	1,635,341
Performance stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Forfeited, shares available for grant (shares)	250,000