Schedule of Adoption of New Revenue Guidance Impact on Condensed Consolidated Balance sheet (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
ASSETS
Accounts receivable, net	$ 1,550		$ 2,789
Deferred costs from commercial product sales			405
Liabilities
Accrued expenses and other current liabilities	15,930		12,449
Deferred revenue, net			3,038
Stockholders' deficit:
Accumulated deficit	(2,883,410)		$ (2,854,898)
Accounting Standards Update 2014-09
ASSETS
Accounts receivable, net		$ 2,678
Liabilities
Accrued expenses and other current liabilities		13,098
Stockholders' deficit:
Accumulated deficit		(2,853,025)
Adjustments | Accounting Standards Update 2014-09
ASSETS
Accounts receivable, net	130	(111)
Deferred costs from commercial product sales	361	(405)
Liabilities
Accrued expenses and other current liabilities	(479)	649
Deferred revenue, net	2,298	(3,038)
Stockholders' deficit:
Accumulated deficit	(1,328)	$ 1,873
Balances Without Adoption of Topic 606 | Accounting Standards Update 2014-09
ASSETS
Accounts receivable, net	1,680
Deferred costs from commercial product sales	361
Liabilities
Accrued expenses and other current liabilities	15,451
Deferred revenue, net	2,298
Stockholders' deficit:
Accumulated deficit	$ (2,884,738)