Difference Between Provision for Income Taxes and Amounts Computed by Applying Federal Statutory Income Tax Rate to Loss before Taxes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation of Provision of Income Taxes [Line Items]
Federal statutory tax									$ (5,329)	$ (5,725)	$ (5,718)
Stock-based compensation									99	83	95
Lobbying expenses									51	112	112
Warrants									(706)	(165)	(13)
Research Grant									0	0	(166)
Gain on investment									0	0	(107)
Foreign rate differential									(53)	(68)	(56)
Expiration of federal net operating losses and credits - tax effected									4,352	1,744	(596)
Change in valuation allowance									1,761	4,158	6,544
Goodwill amortization									48	0	0
Other									19	4	(1)
Provision for income taxes	$ 111	$ 55	$ 41	$ 35	$ 49	$ 44	$ 27	$ 23	$ 242	$ 143	$ 94