Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash Flows From Operating Activities
Net loss	$ (16,092)	$ (16,493)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of leasehold improvements and equipment	363	267
Amortization of intangibles	122	116
Amortization of right of use assets	279	0
Share-based compensation	3,788	3,069
Allowance for doubtful trade receivables	(8)	(127)
Loss from disposal of equipment	0	1
Amortization of covertible notes issuance costs	552	0
Non-cash financing costs	0	70
Other non-cash expense	0	65
Changes in operating assets and liabilities:
Trade receivables	(1,373)	335
Contract assets	4	(7)
Inventories	(2,465)	(730)
Prepaid expenses and other assets	50	(85)
Accounts payable	(224)	3,038
Accrued expenses	(671)	39
Deferred revenue	3,873	0
Customer deposits and other	18	(21)
Principal payments on operating leases	(285)	0
Deferred rent	0	26
Due to officer	0	(100)
Net cash used in operating activities	(12,069)	(10,537)
Cash Flows From Investing Activities
Purchases of leasehold improvements and equipment	(308)	(1,274)
Purchases of intangible assets	(10)	0
Investment in other long-term assets	(47)	0
Net cash used in investing activities	(365)	(1,274)
Cash Flows From Financing Activities
Proceeds from sale of convertible notes	10,000	0
Payment of convertible notes issuance costs	(565)	0
Payment of debt issuance cost	0	(19)
Proceeds from exercise of stock options	271	330
Repurchase of common stock	0	(404)
Principal payments on finance leases	(128)	(96)
Net cash provided by (used in) financing activities	9,578	(189)
Net decrease in cash	(2,856)	(12,000)
Cash, beginning of period, including restricted cash of $0.2 million for 2019	22,616	45,389
Cash, ending of period, including restricted cash $0.2 million for 2019	19,760	33,389
Supplemental Disclosures of Cash Flow Information
Cash payments for interest on finance leases	17	22
Supplemental Schedule of Noncash Operating Activity
Adjustment to retained earnings - cumulative effect of initially applying ASC 606	0	164
Financing lease obligation incurred for prepayment of licensing fees	99	0
Supplemental Schedule of Noncash Investing Activity
Financing lease obligation incurred for purchase of software	143	0
Operating lease obligation incurred for tenant improvement credit received	$ 64	$ 0