Schedule of Adoption of New Revenue Guidance Impact on Consolidated Balance sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
ASSETS
Accounts receivable, net	$ 4,017		$ 2,789
Deferred costs from commercial product sales			405
Liabilities
Accrued expenses and other current liabilities	15,022		12,449
Deferred revenue, net			3,038
Stockholders' deficit:
Accumulated deficit	(2,940,000)		$ (2,854,898)
Accounting Standards Update 2014-09
ASSETS
Accounts receivable, net		$ 2,678
Deferred costs from commercial product sales		0
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	314	(111)
Deferred costs from commercial product sales	875	(405)
Liabilities
Accrued expenses and other current liabilities	(751)	649
Deferred revenue, net	3,937	(3,038)
Stockholders' deficit:
Accumulated deficit	(1,997)	$ 1,873
Balances Without Adoption of Topic 606 | Accounting Standards Update 2014-09
ASSETS
Accounts receivable, net	4,331
Deferred costs from commercial product sales	875
Liabilities
Accrued expenses and other current liabilities	14,271
Deferred revenue, net	3,937
Stockholders' deficit:
Accumulated deficit	$ (2,941,997)