Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Schedule of Loss Before Income Taxes, Domestic and Foreign

Our loss before provision for (benefit from) income taxes was as follows (in thousands): 

	Year Ended December 31,
	2020		2019		2018
United States	$	(23,452)	$	(11,751)	$	(10,653)
Foreign	(219)		(167)		(262)
Loss before provision for income taxes	$	(23,671)	$	(11,918)	$	(10,915)

Components of Provision for Income Taxes

The components of the provision for income taxes are as follows (in thousands): 

	Year Ended December 31,
	2020		2019		2018
Current provision (benefit):
State	$	5	$	5	$	5
Foreign	342		18		(13)
Total current provision (benefit)	347		23		(8)
Deferred provision (benefit):
Foreign	(8)		(6)		(29)
Total deferred provision (benefit)	(8)		(6)		(29)
Provision for (benefit from) income taxes	$	339	$	17	$	(37)

Reconciliation of Provision for Income Taxes Calculated at the Statutory Rate to Provision for Income Taxes

Reconciliation of the provision for (benefit from) income taxes calculated at the statutory rate to our provision for (benefit from) income taxes is as follows (in thousands): 

	Year Ended December 31,
	2020		2019		2018
Tax benefit at federal statutory rate	$	(4,971)	$	(2,503)	$	(2,292)
State taxes	(465)		(1,120)		222
Research and development credits	(811)		(693)		(499)
Foreign operations taxed at different rates	2		1		(17)
Stock-based compensation	132		(3,606)		(2,587)
Other nondeductible items	69		505		(3)
Executive compensation	24		872		838
Change in valuation allowance	6,359		6,561		4,301
Provision for (benefit from) income taxes	$	339	$	17	$	(37)

Significant Components of Deferred Tax Assets and Liabilities

Significant components of our deferred tax assets and liabilities are as follows (in thousands): 

	December 31,
	2020		2019
Deferred tax assets:
Net operating losses	$	72,530	$	68,422
Credits	9,914		8,494
Deferred revenues	1,080		468
Stock-based compensation	2,576		2,338
Reserves and accruals	1,914		1,545
Depreciation	1,115		1,358
Intangible assets	1,714		2,159
Capital losses	25		26
Unrealized gain/loss	400		406
Lease liability	5,626		5,974
Other assets	100		92
Total deferred tax assets:	96,994		91,282
Valuation allowance	(92,126)		(85,768)
Deferred tax liabilities:
Right-of-use assets	(4,848)		(5,514)
Other	(52)		(40)
Total deferred tax liabilities:	(4,900)		(5,554)
Net deferred tax liabilities	$	(32)	$	(40)

Summary of Federal, State and Foreign NOL Carryforwards and Federal Research and Development Tax Credits

The following table sets forth our federal, state and foreign NOL carryforwards and federal research and development tax credits as of December 31, 2020 (in thousands): 

	December 31, 2020
	Amount		Expiration Years
Net operating losses, federal	$	224,475	2022-2037
Net operating losses, federal	$	82,931	Do not expire
Net operating losses, state	$	127,317	2028-2040
Tax credits, federal	$	10,654	2022-2040
Tax credits, state	$	11,977	Do not expire
Net operating losses, foreign	$	778	Various

Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): 

	December 31,
	2020		2019		2018
Balance at beginning of year	$	11,330	$	9,980	$	9,422
Additions based on tax positions related to current year	1,357		1,362		1,087
Reductions to tax provision of prior years	(4)		(12)		(529)
Balance at end of year	$	12,683	$	11,330	$	9,980