Fair Value Measurement - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 05, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Expected volatility rate				50.00%		40.00%
Risk free interest rate				1.10%		0.60%
Expected probability of qualified acquisition				50.00%		90.00%
Qualified acquisition, expected term				6 months		6 months
Net income (loss) attributable to common and participating stockholders		$ (25,824)	$ 17,909	$ (12,535)	$ 68,959
Increase decrease in estimated net income (loss) if percentage of closing stock price ten percent lower				1,300
Increase decrease in estimated net income (loss) if percentage of closing stock price ten percent higher				23,900
Volatility Assumption [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Increase decrease in estimated net income (loss) if percentage of closing stock price ten percent lower				10,500
Increase decrease in estimated net income (loss) if percentage of closing stock price ten percent higher				15,000
Transaction Occurring Assumption [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Increase decrease in estimated net income (loss) if percentage of closing stock price ten percent lower				27,200
Increase decrease in estimated net income (loss) if percentage of closing stock price ten percent higher				$ 2,200
Maximum [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Percentage of closing stock price				10.00%
Estimated net loss				$ 11,200
Maximum [Member] | Volatility Assumption [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Percentage of closing stock price				10.00%
Estimated net loss				$ 2,000
Maximum [Member] | Transaction Occurring Assumption [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Percentage of closing stock price				10.00%
Estimated net loss				$ 14,700
Minimum [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Percentage of closing stock price				10.00%
Estimated net loss				$ 11,400
Minimum [Member] | Volatility Assumption [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Percentage of closing stock price				10.00%
Estimated net loss				$ 2,500
Minimum [Member] | Transaction Occurring Assumption [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Percentage of closing stock price				10.00%
Estimated net loss				$ 14,700
Redeemable Convertible Series B Preferred Stock [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Capital	$ 600,000
Redeemable Convertible preferred stock, shares issued	600,000	600,000		600,000		600,000
Preferred stock liquidation preference per share	$ 1,000
Preferred stock dividend rate calculated on interest rate	3.00%
Conversion ceiling price of common stock		$ 2.25		$ 2.25
Conversion floor price of common stock		1.75		1.75
Redeemable Convertible Series B Preferred Stock [Member] | Maximum [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Conversion ceiling price of common stock		$ 2.25		$ 2.25