Summary of Significant Accounting Policies - Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2015		Jun. 30, 2014		Jun. 30, 2015	Jun. 30, 2014
Numerator
Net income (loss), basic		$ (6,696)		$ 77,536		$ (16,862)	$ 72,584
Income (loss) from discontinued operations		79,160		(14,672)		66,464	(30,651)
Net income (loss), diluted		$ (6,696)		$ 77,536		$ (16,862)	$ 54,114
Denominator
Weighted average common shares outstanding, basic		19,176,000		17,498,000		19,173,000	17,454,000
Weighted average shares outstanding, diluted		19,176,000		17,498,000		19,173,000	17,846,000
Basic net income (loss), Continuing operations, usd per share	[1]	$ (0.35)		$ 4.43		$ (0.88)	$ 4.16
Basic net income (loss), Discontinued operations, usd per share	[1]	4.13		(0.84)		3.47	(1.76)
Diluted net income (loss), Continuing operations, usd per share	[1]	(0.35)		4.43		(0.88)	3.03
Diluted net income (loss), Discontinued operations, usd per share		$ 4.13	[1]	$ (0.84)	[1]	$ 3.47	$ (1.72)	[1]
Common stock options
Denominator
Anti-dilutive securities excluded from computation of earnings per share amount		521,000		1,157,000		297,000	1,586,000
Continuing Operations
Numerator
Common stock warrants		$ 0		$ 0		$ 0	$ 18,470
Equity awards		0		0		0	0
Dilutive Securities, Effect on Basic Earnings Per Share		$ 0		$ 0		$ 0	$ (18,470)
Denominator
Common stock warrants, shares		0		0		0	392,000
Non-employee stock options and restricted stock units, shares		0		0		0	0
Dilutive potential shares of common stock, shares		0		0		0	392,000
Weighted average shares outstanding, diluted		19,176,000		17,498,000		19,173,000	17,846,000
Discontinued Operations
Numerator
Common stock warrants		$ 0		$ 0		$ 0	$ 0
Equity awards		0		0		0	0
Dilutive Securities, Effect on Basic Earnings Per Share		$ 0		$ 0		$ 0	$ 0
Denominator
Common stock warrants, shares		0		0		0	392,000
Non-employee stock options and restricted stock units, shares		0		0		0	0
Dilutive potential shares of common stock, shares		0		0		0	392,000
Weighted average shares outstanding, diluted		19,176,000		17,498,000		19,173,000	17,846,000

[1] The sum of net income (loss) per share amounts may not equal the totals due to rounding.