Note 13 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	2021		2020		2019
Current:
Federal	$	-	$	-	$	-
State		77		124		53
Foreign		247		83		-
		324		207		53
Deferred:
Federal		-		-		-
State		-		-		-
		-		-		-
Total	$	324	$	207	$	53

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	2021			2020			2019
Tax computed at the federal statutory rate	$	(6,045	)	$	(12,540	)	$	(15,830	)
State taxes		(1,072	)		(2,304	)		(2,453	)
Foreign taxes		247			83			—
Permanent items		22,689			13,660			21,834
R&D credits		(3,941	)		(5,231	)		(14,946	)
Prior year adjustment		916			(2,116	)		(2,792	)
Change in valuation allowance		(12,470	)		8,655			14,240
Total provision	$	324		$	207		$	53

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	2021			2020			2019
Deferred tax assets:
Net operating loss carryforwards	$	258,390		$	261,472		$	260,555
Business credit carryforwards		59,514			55,574			50,343
Compensation		40,647			58,112			60,967
Accrued legal verdict		14,144			11,880			7,624
Carryforward of disallowed interest		4,537			3,093			2,839
Accrued expenses		104			561			9
Lease liabilities		4,839			5,657			6,145
Other deferred tax assets		1,306			804			13
Subtotal		383,481			397,153			388,495
Deferred tax liabilities:
Lease right-of-use assets		(3,470	)		(4,099	)		(4,505	)
Inventory		406			(21	)		—
Other deferred tax liabilities		(318	)		(464	)		(76	)
Subtotal		(3,382	)		(4,584	)		(4,581	)
Total deferred tax assets		380,099			392,569			383,914
Valuation allowance		(380,099	)		(392,569	)		(383,914	)
Net deferred tax assets	$	—		$	—		$	—

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

	2021		2020		2019
Unrecognized tax benefits - January 1	$	3,276	$	1,968	$	8,777
Gross decreases - tax positions in a prior period		—		—		(8,422	)
Gross increases - tax positions in a current period		985		1,308		1,613
Unrecognized tax benefits - December 31	$	4,261	$	3,276	$	1,968