Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash Flows From Operating Activities
Net income	$ 1,174	$ 1,238
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	728	170
Stock-based compensation	1,021	1,014
Write off of deferred costs		57
Provision for excess inventories	266	93
Deferred income taxes	(15)	(69)
Changes in operating assets and liabilities:
Accounts receivable	156	(255)
Inventory	(4,910)	245
Prepaid expenses and other current assets	52	(31)
Other assets	2	(54)
Accounts payable	590	259
Accrued expenses	320	401
Customer deposits	3,396	191
Lease liabilities	(280)
Other liabilities	(240)	17
Net cash provided by operating activities	2,260	3,276
Cash Flows From Investing Activities
Purchase of property and equipment	(267)	(276)
Net cash used in investing activities	(267)	(276)
Cash Flows From Financing Activities
Net proceeds from exercise of stock options	128	367
Payment for shares withheld for tax withholdings on vesting of restricted stock units	(57)
Payment of deferred costs		(57)
Net cash provided by financing activities	71	310
Net increase in cash and cash equivalents	2,064	3,310
Cash and cash equivalents at beginning of period	25,941	21,536
Cash and cash equivalents at end of period	28,005	24,846
Supplemental Disclosure of Cash Flow Information
Cash paid for income taxes	35	43
Supplemental Disclosure of Noncash Investing and Financing Information
Property and equipment purchased but not yet paid	33	40
Vesting of early exercised options	$ 51	$ 56