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 income (loss)	$ (283)	$ 674
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	489	107
Stock-based compensation	684	463
Provision for excess inventories	234	41
Deferred income taxes	(113)	(235)
Changes in operating assets and liabilities:
Accounts receivable	81	(62)
Inventory	(1,808)	739
Prepaid expenses and other current assets	(17)	173
Other assets	(3)	(64)
Accounts payable	410	279
Accrued expenses	59	(8)
Customer deposits	1,057	23
Lease liabilities	(155)
Other liabilities	(148)	10
Net cash provided by operating activities	487	2,140
Cash Flows From Investing Activities
Purchase of property and equipment	(225)	(143)
Net cash used in investing activities	(225)	(143)
Cash Flows From Financing Activities
Net proceeds from exercise of stock options	66	281
Payment for shares withheld for tax withholdings on vesting of restricted stock units	(31)
Payment of deferred costs		(18)
Net cash provided by financing activities	35	263
Net increase in cash and cash equivalents	297	2,260
Cash and cash equivalents at beginning of period	25,941	21,536
Cash and cash equivalents at end of period	26,238	23,796
Supplemental Disclosure of Cash Flow Information
Cash paid for income taxes	13	23
Supplemental Disclosure of Noncash Investing and Financing Information
Vesting of early exercised options	$ 34	36
Property and equipment purchased but not yet paid		54
Unpaid deferred costs		$ 39