Net Income (Loss) Per Common Share - Schedule of Potentially Dilutive Securities (Detail) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive common shares excluded from net loss per common share computations	12,611	12,804
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive common shares excluded from net loss per common share computations	6,503	6,898
Convertible Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive common shares excluded from net loss per common share computations	5,050	5,050
Restricted stock units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive common shares excluded from net loss per common share computations	532	383
Stock appreciation rights [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive common shares excluded from net loss per common share computations	506	427
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive common shares excluded from net loss per common share computations	20	46