Stock Incentive and Employee Stock Purchase Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 16, 2014	Nov. 15, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of option awards recognized as expense	$ 3,588,000	$ 3,443,000	$ 7,500,000
Total intrinsic value of options exercised	449,000
Number of shares issued under the ESPP	114,791	0	1,086,837
Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of option awards recognized as expense	1,300,000
Stock options outstanding under the 2009 Omnibus Incentive Compensation Plan and previous plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock issued upon the exercise of stock options	10,000,000
Total fair value of option awards recognized as expense	776,000	800,000	1,700,000
Duration of the options granted	10 years
Rate of options exercisable after one year	33.30%
Total intrinsic value of options exercised	96,000	44,000	0
Total unrecognized share-based compensation cost	1,777,000
Expected recognition period	2 years 8 months 12 days
Weighted average fair value of option awards granted per share	$ 1.48	$ 1.20	$ 1.97
Stock options outstanding under the 2009 Omnibus Incentive Compensation Plan and previous plans | New Hire
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted vesting period	24 months
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of option awards recognized as expense	2,900,000	2,600,000	3,400,000
Expected recognition period	2 years 8 months 12 days
Number of RSUs awarded to employees	2,658,956	447,703	1,015,638
RSUs (restricted stock units) vesting rights percentage	33.33%
Aggregate fair value of awards	5,743,000	900,000	3,400,000
Unrecognized compensation expense related to non-vested RSUs	3,000,000
Restricted stock units | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of RSUs price per unit at fair value	$ 1.60	$ 1.74	$ 1.28
Restricted stock units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of RSUs price per unit at fair value	$ 3.55	$ 4.17	$ 3.58
Shares available under the Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to non-vested RSUs					1,000,000
Percentage of lower limit value of common stock	85.00%
Maximum limit of payroll deductions (percent)	10.00%
Number of shares issue that the ESPP authorizes for purchase by eligible employees				1,500,132
Amount received in cash through employee withholdings	192,000	0	1,600,000
Total fair value of awards recognized as expenses	$ 101,000	$ 0	$ 1,400,000