Summary of Geographic Information Related to Company's Total Revenues and Long Lived Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 1,375	$ 1,563	$ 2,871	$ 3,151
Percentage of total revenue			100.00%	100.00%
Long-lived assets	7,581		7,581		8,276
Percentage of long-lived assets	100.00%		100.00%		100.00%
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue			2,777	3,151
Percentage of total revenue			97.00%	100.00%
Long-lived assets	7,549		7,549		8,276
Percentage of long-lived assets	100.00%		100.00%		100.00%
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue			94
Percentage of total revenue			3.00%	0.00%
Long-lived assets	32		32
Percentage of long-lived assets	0.00%		0.00%		0.00%
Total International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue			94
Percentage of total revenue			3.00%	0.00%
Long-lived assets	$ 32		$ 32
Percentage of long-lived assets	0.00%		0.00%		0.00%