Summary of Significant Accounting Policies - Summary of Reconciliation of Amounts in Previously Reported Consolidated Financial Statements - Statement of Stockholders' Equity (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Total stockholders' equity	$ 583,829	$ 556,607
Accumulated Deficit [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Total stockholders' equity	$ (1,377,823)	(1,404,670)
As Reported [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Total stockholders' equity		546,716
As Reported [Member] | Accumulated Deficit [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Total stockholders' equity		(1,414,561)
Adjustment [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Total stockholders' equity		9,891
Adjustment [Member] | Accumulated Deficit [Member]
Quantifying Misstatement In Current Year Financial Statements [Line Items]
Total stockholders' equity		$ 9,891