Stock-Based Compensation - Summary of Stock Option Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding [Roll Forward]
Options outstanding, beginning balance, shares	1,099,106
Options Outstanding Granted	689,550
Options Outstanding Exercised	(11,841)
Options outstanding Expired or cancelled	(88,568)
Options outstanding Forfeited	(22,633)
Options outstanding, ending balance, shares	1,665,614
Options exercisable, ending balance, shares	941,331
Options outstanding, beginning balance, Weighted Average Exercise Price	$ 9.06
Weighted Average Exercise Price Granted	$ 7.20
Weighted Average Exercise Price Exercised	$ 7.11
Weighted Average Exercise Price Expired or Cancelled	$ 7.90
Weighted Average Exercise Price Forfeited	$ 6.45
Options outstanding, ending balance, Weighted Average Exercise Price	$ 8.40
Options outstanding, Exercisable at End of Year, Weighted Average Exercise Price	$ 9.35