Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
CASH FLOWS PROVIDED BY (USED IN) OPERATING ACTIVITIES:
Net loss	$ (4,623)	$ (4,103)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	454	489
Increase (decrease) in allowance for doubtful accounts	(3)	6
Loss on disposal and write-down of fixed assets	0	1
Increase in accrued investment income	(110)	(43)
Stock-based compensation	1,457	746
Adjustment to contingent consideration	0	(318)
Change in operating assets and liabilities:
Accounts receivable	367	1,009
Inventories	(681)	323
Deferred cost of goods sold	(628)	(20)
Other current assets	(242)	200
Accounts payable	586	(558)
Accrued liabilities	259	(1,176)
Deferred revenues	1,004	340
Deferred rent	(65)	81
Net cash used in operating activities	(2,225)	(3,023)
CASH FLOWS PROVIDED BY (USED IN) INVESTING ACTIVITIES:
Purchases of available-for-sale short-term investments	(23,875)	(23,955)
Proceeds from maturities and sales of available‑for‑sale short‑term investments	24,000	29,155
Change in other long-term assets	(98)	160
Capital expenditures	(209)	(117)
Net cash provided by (used in) investing activities	(182)	5,243
CASH FLOWS PROVIDED BY (USED IN) FINANCING ACTIVITIES:
Repurchase of common stock from employees for payment of taxes on vesting of restricted stock units and upon exercise of stock options	(240)	(43)
Net cash used in financing activities	(240)	(43)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	105	(65)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(2,542)	2,112
CASH AND CASH EQUIVALENTS:
Beginning of period	9,803	7,691
End of period	7,261	9,803
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for income taxes	151	169
Non-cash transfer of restricted investments to available-for-sale short-term investments	$ 0	$ 151