Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating activities:
Net loss	$ (3,224)	$ (2,142)	$ (4,992)	$ (4,305)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization			562	525
Stock-based compensation			342	547
Impairment of long-lived assets	1,676		1,676
Loss on disposal of fixed assets	5		5
Changes in operating assets and liabilities:
Trade accounts receivable			40	93
Inventory			(56)	(198)
Prepaid expenses and other current assets			163	117
Accounts payable and accrued liabilities			(202)	(155)
Deferred revenue			6	(7)
Net cash used in operating activities			(2,456)	(3,383)
Investing Activities:
Purchases of property and equipment			(597)	(71)
Proceeds from disposal of fixed assets			5
Net cash used in investing activities			(592)	(71)
Financing Activities:
Proceeds from exercise of stock options			14	47
Net cash provided by financing activities			14	47
Net decrease in cash and restricted cash			(3,034)	(3,407)
Cash and restricted cash at beginning of period			35,234	41,314
Cash and restricted cash at end of period	$ 32,200	$ 37,907	$ 32,200	$ 37,907