Stock-Based Compensation (Detail) - Restricted Stock Unit Activity - Restricted Stock	9 Months Ended
	Sep. 30, 2015 $ / shares shares
Shares (in shares)
Beginning balance (in shares)	977,069
Granted (in shares)	789,500
Forfeited (in shares)	(192,248)
Vested (in shares)	(351,938)
Ending balance (in shares)	1,222,383
Weighted Average Grant Date Fair Value (in Dollars per share)
Beginning balance (in dollars per share) | $ / shares	$ 5.36
Granted (in dollars per share) | $ / shares	3.33
Forfeited (in dollars per share) | $ / shares	4.70
Vested (in dollars per share) | $ / shares	5.17
Ending balance (in dollars per share) | $ / shares	$ 4.21