Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net (loss) income	$ (388)	$ 70
Adjustments to reconcile net (loss) income to operating cash flow:
Depreciation and amortization	818	843
Bad debt expense	0	20
Reserve for inventory obsolescence	30	130
Stock-based compensation	353	386
Non-cash interest expense	6	0
Deferred revenue	(24)	(24)
(Gain) on sale of property and equipment	(25)	(15)
(Increase) decrease in operating assets:
Accounts receivable	(1,099)	467
Inventories	(727)	52
Refundable income taxes	1,490	(448)
Prepaid expenses and other current assets	(57)	(185)
Increase (decrease) in operating liabilities:
Accounts payable	1,031	288
Accrued expenses	(207)	(629)
Accrued income taxes	(19)	(102)
Net cash provided by operating activities	1,182	853
Cash flows from investing activities:
Purchases of property and equipment	(137)	(879)
Proceeds from sale of property and equipment	31	32
Purchase of investments	(15)	0
Net cash used in investing activities	(121)	(847)
Cash flows from financing activities:
Repurchase of Treasury stock	(205)	(1,052)
Repayment of line of credit	(1,330)	0
Repayment of notes payable	0	(210)
Net cash used in financing activities	(1,535)	(1,262)
Net decrease in cash and cash equivalents	(474)	(1,256)
Cash and cash equivalents at the beginning of the period	2,998	4,978
Cash and cash equivalents at the end of the period	2,524	3,722
Supplemental cash flow information:
Cash paid for income taxes, net of (refunds)	(1,525)	587
Cash paid for interest	84	63
Non-cash investing activities:
Right-of-use assets recognized at ASU 2016-02 transition	944	0
Operating lease liability recognized at ASU 2016-02 transition	997	0
Right-of-use assets and operating lease liabiliites recognized after ASU 2016-02 transition	$ 242	$ 0