Stock-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		0 Months Ended	9 Months Ended	0 Months Ended													9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Mar. 31, 2014 Employee Two	Sep. 30, 2014 Employee Stock Option	Sep. 15, 2014 Vested options held by 1 employee	Sep. 08, 2014 Vested options held by 1 employee	Mar. 31, 2014 Vested options held by 1 employee	Jun. 14, 2013 Vested options held by 1 employee	May 31, 2013 Vested options held by 1 employee	Jun. 14, 2013 Vested options held by 1 employee Before Extension	May 31, 2013 Vested options held by 1 employee Before Extension	Jun. 14, 2013 Vested options held by 1 employee After Extension	May 31, 2013 Vested options held by 1 employee After Extension	Sep. 08, 2014 Unvested options held by 1 employee	Sep. 15, 2014 Unvested options held by 1 employee	Sep. 08, 2014 Unvested options held by 1 employee	Mar. 31, 2014 Unvested options held by 1 employee	Sep. 30, 2014 Unvested Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, granted	10,000	125,000	114,300	1,551,400
Weighted-average grant date fair value	$ 2.29	$ 2.47	$ 3.15	$ 1.94
Unrecognized compensation costs	$ 4.8		$ 4.8
Expected recognition period						1 year 5 months 23 days														1 year 29 days
Shares vested					33,333		39,167	82,834	71,167	71,167	66,667
Shares vesting period									9 months			3 months	3 months	12 months	12 months	3 months
Shares unvested																	113,333	23,333	66,667
Unrecognized compensation costs related to unvested restricted stock outstanding																				$ 0.4