Net Income (Loss) Per Common Share - Schedule of Potentially Dilutive Securities (Detail) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive common shares excluded from net loss per common share computations	12,551	12,979	9,503
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	6,615	7,038	8,604
Convertible notes, principal amount [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
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	503	471	525
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	311	374	203
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive common shares excluded from net loss per common share computations	52
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	46
Performance shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive common shares excluded from net loss per common share computations			125