Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Summary of restricted cash

	As of December 31,
	2020		2019
	(in thousands)
Fixed deposits		—		171
	$	—	$	171

Summary of share repurchase activity

Periods	Total number of shares purchased		Average price paid per share		Total number of shares purchased as part of publicly announced program		Approximate dollar value of shares that may yet be purchased under the program (in thousands)
January 1, 2020, to December 31, 2020		295,946	$	8.10		295,546	$	3,000
Total		295,946					$	3,000

Schedule of allowance for doubtful accounts

	Year ended December 31,
	2020			2019
	(in thousands)
Beginning balance	$	40		$	7
Charges to costs and expenses		(20	)		33
Account write-offs, less recoveries		(17	)		—
Ending balance	$	3		$	40

Schedule of inventories

	As of December 31,
	2020		2019
	(in thousands)
Raw materials	$	468	$	468
Work-in-process		614		901
Finished goods		459		809
	$	1,541	$	2,178

Schedule of property and equipment

	As of December 31,
	2020			2019
	(in thousands)
Machinery, equipment and tooling	$	3,343		$	3,341
Buildings		1,711			1,711
Information systems		835			835
Land and land improvements		594			594
Furniture and fixtures		8			8
Total cost		6,491			6,489
Accumulated depreciation and amortization		(4,009	)		(3,842	)
Property and equipment, net	$	2,482		$	2,647

Schedule of property and equipment, estimated useful lives

Asset description	Life
Buildings	39 years
Machinery, equipment and tooling	3-10 years
Furniture and fixtures	7 years
Information systems	3 years

Schedule of product warranty liability

	Year ended December 31,
	2020			2019
	(in thousands)
Balance, beginning of period	$	4		$	8
Charged to cost of sales		18			31
Actual product warranty expenditures		(20	)		(35	)
Balance, end of period	$	2		$	4