Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Summary of restricted cash

	As of December 31,
	2019		2018
		(in thousands)
Fixed deposits		171		169
	$	171	$	169

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, 2019, to December 31, 2019		67,141	$	7.97		67,141		2,399
Total		67,141					$	2,399

Schedule of allowance for doubtful accounts

	Year ended December 31,
	2019		2018
	(in thousands)
Beginning balance	$	7	$	7
Charges to costs and expenses		33		—
Account write-offs, less recoveries		—		—
Ending balance	$	40	$	7

Schedule of inventories

	As of December 31,
	2019		2018
	(in thousands)
Raw materials	$	468	$	468
Work-in-process		901		1,322
Finished goods		809		340
	$	2,178	$	2,130

Schedule of property and equipment

	As of December 31,
	2019			2018
	(in thousands)
Machinery, equipment and tooling	$	3,341		$	3,293
Buildings		1,711			1,686
Information systems		835			819
Land and land improvements		594			594
Furniture and fixtures		8			8
Total cost		6,489			6,400
Accumulated depreciation and amortization		(3,842	)		(3,672	)
Property and equipment, net	$	2,647		$	2,728

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,
	2019			2018
	(in thousands)
Balance, beginning of period	$	8		$	15
Charged to cost of sales		31			23
Actual product warranty expenditures		(35	)		(30	)
Balance, end of period	$	4		$	8