Operations - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2013 Employee	Jun. 30, 2012	Dec. 31, 2012 Employee	Dec. 31, 2011
Operations Textual [Abstract]
Number of employees	4		4
Net cash used in operating activities	$ (688)	$ (798)	$ (1,500)	$ (1,900)
Minimum period to operate company on basis of sufficient capital resources and liquidity	1 year