Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Summary of allowance for doubtful accounts

	September 30, 2018		December 31, 2017
	(in thousands)
Beginning balance	$	7	$	31
Charges to costs and expenses		1		(20	)
Accounts charged off, less recoveries		—		(4	)
Ending balance	$	8	$	7

Summary of inventories

	September 30, 2018		December 31, 2017
	(in thousands)
Raw materials	$	469	$	476
Work-in-process		1,875		2,334
Finished goods		218		220
	$	2,562	$	3,030

Summary of property and equipment

	September 30, 2018			December 31, 2017
	(in thousands)
Leasehold improvements	$	3,620		$	4,624
Machinery, equipment and tooling		3,293			6,105
Buildings		1,686			—
Information systems		819			819
Land and land improvements		594			—
Furniture and fixtures		8			8
Total cost		10,020			11,556
Accumulated depreciation and amortization		(7,247	)		(10,741	)
Property and equipment, net	$	2,773		$	815