Summary of Significant Accounting Policies - Summary of Reconciliation of Amounts in Previously Reported Consolidated Financial Statements - Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Accounts receivable	$ 40,553	$ 44,423
Total current assets	76,733	250,415
Total assets	1,210,246	1,198,644
Accrued liabilities	24,981	55,044
Total current liabilities	124,376	131,519
Total liabilities	627,214	642,037
Accumulated deficit	(1,383,023)	(1,404,670)
Total stockholders' equity	583,032	556,607
Total liabilities and stockholders' equity	$ 1,210,246	1,198,644
As Reported [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Accounts receivable		43,638
Total current assets		249,630
Total assets		1,197,859
Accrued liabilities		64,150
Total current liabilities		140,625
Total liabilities		651,143
Accumulated deficit		(1,414,561)
Total stockholders' equity		546,716
Total liabilities and stockholders' equity		1,197,859
Adjustment [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Accounts receivable		785
Total current assets		785
Total assets		785
Accrued liabilities		(9,106)
Total current liabilities		(9,106)
Total liabilities		(9,106)
Accumulated deficit		9,891
Total stockholders' equity		9,891
Total liabilities and stockholders' equity		$ 785