Income Taxes - Significant Components of Company's Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Accrued compensation	$ 13	$ 184
Accrued liabilities	235	149
Tax loss carryforwards	38,042	37,986
Intangible assets	268	286
Share-based compensation	666	814
Tax credits	8,141	6,917
Facility financing lease obligation	0	1,847
Research and development service obligation	6,620	0
Right-of-use lease liabilities	1,436	0
Deferred revenue	572	588
Other	54	10
Total deferred tax assets	56,047	48,781
Less valuation allowance	(54,430)	(46,604)
Net deferred tax asset	1,617	2,177
Deferred tax liabilities:
Fixed assets	(1,014)	(2,032)
Right-of-use lease assets	(421)	0
Other	(182)	(145)
Net noncurrent deferred tax asset (liability)	$ 0	$ 0