Schedule of Adoption of New Revenue Guidance Impact on Condensed Consolidated Balance sheet (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
ASSETS
Accounts receivable, net	$ 2,848		$ 2,789
Deferred costs from commercial product sales			405
Liabilities
Accrued expenses and other current liabilities	14,075		12,449
Deferred revenue, net			3,038
Stockholders' deficit:
Accumulated deficit	(2,906,085)		$ (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	300	(111)
Deferred costs from commercial product sales	406	(405)
Liabilities
Accrued expenses and other current liabilities	(479)	649
Deferred revenue, net	2,690	(3,038)
Stockholders' deficit:
Accumulated deficit	(1,506)	$ 1,873
Balances Without Adoption of Topic 606 | Accounting Standards Update 2014-09
ASSETS
Accounts receivable, net	3,148
Deferred costs from commercial product sales	406
Liabilities
Accrued expenses and other current liabilities	13,596
Deferred revenue, net	2,690
Stockholders' deficit:
Accumulated deficit	$ (2,907,591)