Reconciliations of Reported Income Tax Provision to Amount that would Result by Applying Federal Statutory Rate (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Income tax expense (benefit) at statutory rate	$ 629	$ (14,702)	$ (39,718)
Goodwill impairment charge		1,758	30,136
Change in valuation allowance	4,886	30,284
Nondeductible stock-based compensation expense	1,039	1,258	1,849
Research and development tax credit	(496)	(639)	(858)
Worthless stock deduction			(1,646)
State income tax benefit	(322)	(692)	(1,156)
Original issue discount amortization	(241)	(2,993)	(1,678)
Other	(1,966)	2,317	(2,420)
Total provision (benefit) for income taxes	$ 3,529	$ 16,591	$ (15,491)
Income tax expense (benefit) at statutory rate	35.00%	35.00%	35.00%
Goodwill impairment charge		(4.20%)	(26.60%)
Change in valuation allowance	271.70%	(72.10%)
Nondeductible stock-based compensation expense	57.80%	(3.00%)	(1.60%)
Research and development tax credit	(27.60%)	1.50%	0.80%
Worthless stock deduction			1.50%
State income tax benefit	(17.90%)	1.70%	1.00%
Original issue discount amortization	(13.40%)	7.10%	1.50%
Other	(109.40%)	(5.50%)	2.10%
Income tax provision (benefit)	196.20%	(39.50%)	13.70%