Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Taxes [Abstract]

Components Of Deferred Tax Assets

	December 31,
	2018		2017
Temporary differences	$	111	$	36
Credits		5,330		1,536
Stock compensation		2,630		3,067
Net operating loss carryforwards		15,365		7,715
Total deferred tax assets before valuation allowance		23,436		12,354
Valuation allowance		(22,696)		(11,491)
Total deferred tax assets after valuation allowance		740		863
Technology deferred tax liability		(740)		(863)
Net deferred tax assets	$	—	$	—

Reconcilement Of Tax Rates

	Year Ended December 31,
	2018		2017		2016
U.S. federal statutory tax rate	(21.0)	%	(35.0)	%	(35.0)	%
Valuation allowance	28.0		23.0		42.0
Tax reform	(2.0)		18.0		—
Permanent differences	2.0		1.0		2.0
State tax benefit and other	(7.0)		(7.0)		(9.0)
Effective tax rate	—	%	—	%	—	%

Reconciliation Of Unrecognized Tax Benefit Accounts

	December 31,
	2018		2017
Balance at the beginning of the year	$	512	$	213
Gross increases - tax positions in prior periods		—		37
Gross decreases - tax positions in prior periods		—		—
Gross increases - tax position in current period		365		262
Settlements		—		—
Lapses in statutes of limitations		—		—
Balance at the end of the year	$	877	$	512