Stock-Based Compensation - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended				6 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Minimum [Member]	Sep. 30, 2013 Maximum [Member]	Sep. 30, 2013 Common stock [Member]	Sep. 30, 2013 2005 Stock Option [Member]	Sep. 30, 2013 Employee Stock Purchase Plan [Member]	Sep. 30, 2013 Stock options [Member]	Sep. 30, 2013 Restricted stock [Member]	Sep. 30, 2012 Restricted stock [Member]	Sep. 30, 2013 Restricted stock [Member]	Sep. 30, 2012 Restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, granted										120,000
Restricted stock, granted													1,500,000
Restricted stock, weighted average grant date fair value													$ 1.70
Stock options, weighted average grant date fair value										$ 0.63
Restricted stock vesting period					12 months	48 months
Number of shares available for future grants								1,900,000
Employee stock purchase plan (ESPP), shares							19,000
Shares purchased/granted at a fair value									$ 0.44
Stock-based compensation	$ 821	$ 898	$ 2,747	$ 3,052							$ 100	$ 100	$ 300	$ 300