Summary of Significant Accounting Policies - Summary of Reconciliation of Amounts in Previously Reported Consolidated Financial Statements - Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Accounts receivable	$ 77,609	$ 44,423	$ 27,729
Total current assets	107,062	250,415	269,637
Total assets	1,223,527	1,198,644	1,266,665
Accounts payable	76,174	44,049	36,854
Accrued liabilities	41,662	55,044	10,758
Total current liabilities	149,594	131,519	101,275
Total liabilities	651,173	642,037	633,291
Accumulated deficit	(1,396,145)	(1,404,670)	(1,197,935)	$ (236,144)
Total stockholders' equity	572,354	556,607	633,374	1,155,912
Total liabilities and stockholders' equity	$ 1,223,527	1,198,644	1,266,665
As Reported [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Accounts receivable		43,638	27,476
Total current assets		249,630	269,384
Total assets		1,197,859	1,266,412
Accounts payable			34,717
Accrued liabilities		64,150	25,462
Total current liabilities		140,625	113,842
Total liabilities		651,143	645,858
Accumulated deficit		(1,414,561)	(1,210,755)	(239,345)
Total stockholders' equity		546,716	620,554	1,152,711
Total liabilities and stockholders' equity		1,197,859	1,266,412
Adjustment [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Accounts receivable		785	253
Total current assets		785	253
Total assets		785	253
Accounts payable			2,137
Accrued liabilities		(9,106)	(14,704)
Total current liabilities		(9,106)	(12,567)
Total liabilities		(9,106)	(12,567)
Accumulated deficit		9,891	12,820	3,201
Total stockholders' equity		9,891	12,820	$ 3,201
Total liabilities and stockholders' equity		$ 785	$ 253