Income (Loss) per Common Share - Computation of Basic and Diluted Net Income (Loss) Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Numerator:
Net income (loss):	$ (33,763)	$ (3,777)	$ (26,697)	$ 18,977
Total dividends on preferred stocks			(300)	(300)
Numerator for basic net income (loss) per common share - net income (loss) applicable to common stock	(33,763)	(3,777)	(26,997)	18,677
Dividends on preferred stocks assumed to be converted, if dilutive			300	300
Numerator for diluted net income (loss) per common share	$ (33,763)	$ (3,777)	$ (26,697)	$ 18,977
Denominator:
Denominator for basic net income (loss) per common share - weighted-average shares	22,799,007	22,595,634	22,741,012	22,557,935
Effect of dilutive securities:
Convertible preferred stocks				916,666
Stock options				187,026
Dilutive potential common shares				1,103,692
Denominator for dilutive net income (loss) per common share - adjusted weighted-average shares and assumed conversions	22,799,007	22,595,634	22,741,012	23,661,627
Basic net income (loss) per common share	$ (1.48)	$ (0.17)	$ (1.19)	$ 0.83
Diluted net income (loss) per common share	$ (1.48)	$ (0.17)	$ (1.19)	$ 0.80
Series B Preferred Stock [Member]
Numerator:
Total dividends on preferred stocks			$ (240)	$ (240)
Series D Preferred Stock [Member]
Numerator:
Total dividends on preferred stocks			$ (60)	$ (60)