Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities:
Net loss	$ (1,441)	$ (1,643)
Reconciliation of net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	484	489
Stock-based compensation expense	341	118
Changes in operating assets and liabilities:
Accounts receivable	2,107	(625)
Inventories	(72)	414
Prepaid expenses and other current assets	48	(406)
Other non-current assets		18
Accounts payable	(1,363)	1,927
Accrued expenses and other	(1,039)	(1,287)
Deferred rent	(9)	17
Deferred revenue	806	1,349
Net cash (used in) provided by operating activities	(138)	371
Investing activities:
Purchases of property and equipment	(520)	(720)
Net cash used in investing activities	(520)	(720)
Financing activities:
Proceeds from equipment loans	1,501
Principal payments on debt	(79)	(57)
Dividends paid	(7)	(7)
Net cash provided by (used in) financing activities	1,415	(64)
Effect of exchange rate changes on cash and cash equivalents	8	(18)
Net increase (decrease) in cash and cash equivalents	765	(431)
Cash and cash equivalents, beginning of period	20,994	13,901
Cash and cash equivalents, end of period	21,759	13,470
Supplemental cash flow information
Cash paid for interest	23	$ 22
Supplemental noncash investing
Purchases of equipment through accounts payable and accrued expenses	$ 215