Long Term Obligations - 6.25% Convertible Notes due 2018 - Additional Information (Detail) - USD ($)			3 Months Ended	6 Months Ended
	Apr. 17, 2017	Apr. 14, 2017	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Mar. 28, 2017	Mar. 17, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Interest rate of convertible notes			6.25%	6.25%
Cash and cash equivalents			$ 12,982,000	$ 12,982,000	$ 22,248,000			$ 21,228,000
Loss on extinguishment of debt			$ 5,158,000	$ 7,434,000	$ 336,000
6.25% Convertible Notes Due 2018 [Member]
Debt Instrument [Line Items]
Debt instrument, repurchase amount per note							$ 1,025
Debt instrument, repurchased face amount per note							$ 1,000
Interest rate of convertible notes		6.25%	6.25%	6.25%		6.25%	6.25%
Proceeds from convertible notes				$ 94,000,000
Principal amount of convertible notes		$ 83,956,000
Maturity date		Apr. 14, 2017		May 01, 2018
Repayment of notes	$ 90,011,000
Principal	83,956,000
Accrued interest	2,420,000
Premium	3,148,000
Fees	487,000
Restricted cash and cash equivalents	83,956,000		$ 10,044,000	$ 10,044,000
Cash and cash equivalents	6,055,000
Convertible notes	$ 10,044,000		10,044,000	$ 10,044,000		$ 94,000,000		$ 94,000,000
Loss on extinguishment of debt			$ 5,160,000