Supplementary Balance Sheet Information (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure Text Block Supplement [Abstract]

Components of Accounts Receivable, Net of Allowance

Accounts Receivable, net:

	December 31,
(in thousands):	2019		2018
Trade	$	8,760	$	10,990
Royalties		—		71
Other		—		51
Total receivables, net	$	8,760	$	11,112

Components of Inventory

Inventory:

	December 31,
(in thousands):	2019		2018
Raw materials	$	3,689	$	3,590
Work-in-process		1,064		1,435
Finished goods		6,242		7,223
Inventory	$	10,995	$	12,248

Summary of Property, Plant, and Equipment

Property, Plant, and Equipment, net:

	December 31,
(in thousands):	2019			2018
Building	$	209		$	213
Leasehold improvements		2,004			2,004
Equipment and computers		7,479			7,277
Furniture and fixtures		634			634
Construction in progress		27			25
Total property, plant, and equipment before depreciation and    land		10,353			10,153
Less: accumulated depreciation		(9,322	)		(8,344	)
Total property, plant, and equipment, net before land		1,031			1,809
Land		162			166
Property, plant, and equipment, net	$	1,193		$	1,975

Components of Accrued Liabilities

Accrued Liabilities:

	December 31,
	2019		2018
Payroll and benefits	$	1,726	$	2,400
Warranty accrual, current portion		865		861
Taxes		242		714
Accrued professional services		330		1,044
Accrued insurance premium		546		328
Patent litigation settlement		—		1,500
Lease liability		323		—
Other		712		691
Accrued liabilities	$	4,744	$	7,538