Summary of Significant Accounting Policies - Summary of Reconciliation of Amounts in Previously Reported Consolidated Financial Statements - Statement of Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Net loss	$ 11,494	$ (73,163)	$ 38,341	$ (118,697)
Accounts receivable			3,992	(1,595)
Accounts payable and accrued liabilities			$ 5,796	(7,670)
As Reported [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Net loss		(73,011)		(113,698)
Accounts receivable				(1,238)
Accounts payable and accrued liabilities				(13,026)
Adjustment [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Net loss		$ (152)		(4,999)
Accounts receivable				(357)
Accounts payable and accrued liabilities				$ 5,356