Components of Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Net operating losses	$ 257,900	$ 260,600
Research and development credits	33,500	29,000
Capitalized research and development	58,900	45,700
Share-based compensation expense	10,900	6,900
Deferred revenue	4,300	800
Deferred gain on sales leaseback	5,000	7,200
Intangibles	6,900	10,600
Cease-use expense	700	1,100
Fixed assets	400	500
Other	3,900	4,700
Total deferred tax assets	382,400	367,100
Valuation allowance	(382,400)	(367,100)
Net deferred tax assets	$ 0	$ 0