Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current deferred tax asset:
Accrued liabilities	$ 16	$ 59
Valuation allowance	(16)	(59)
Net current deferred tax asset
Non-current deferred tax assets:
Fixed and intangible assets	54	392
Net operation loss carry-forwards	119,797	120,497
AMT credit carry-forwards	74	74
Capital loss and charitable carry-forwards	3	2,749
Research and experimental tax credits	10,307	10,986
Stock compensation	423	360
Deferred revenue	16,621	12,627
Interest	1,101	6,686
Valuation allowance	(148,380)	(154,371)
Net non-current deferred tax asset	$ 0	$ 0