Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash Flows From Operating Activities
Net income	$ 4,377	$ 3,853
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	101	102
Stock-based compensation	515	371
Amortization of premium on available-for-sale investments	56	49
Loss on disposal of long-lived assets		6
Inventory valuation adjustment	182	5
Deferred income taxes	(422)	72
Noncash lease expense	190	177
Changes in operating assets and liabilities:
Accounts receivable	230	(2)
Inventory	(1,840)	(1,377)
Prepaid expenses and other current assets	317	61
Other assets	8	9
Accounts payable	(288)	1,073
Accrued expenses	1,399	(430)
Customer deposits	64	2,078
Lease liabilities	(53)	(43)
Other liabilities	(99)	(149)
Net cash provided by operating activities	4,737	5,855
Cash Flows From Investing Activities
Purchase of property and equipment	(246)	(36)
Purchase of debt securities	(2,005)
Proceeds from maturities of debt securities	1,250	5,705
Net cash (used in) provided by investing activities	(1,001)	5,669
Cash Flows From Financing Activities
Payment of dividends	(4,504)
Net proceeds from exercise of stock options	141	70
Payment for shares withheld for tax withholdings on vesting of restricted stock units	(82)	(29)
Net cash (used in) provided by financing activities	(4,445)	41
Net (decrease) increase in cash and cash equivalents	(709)	11,565
Cash and cash equivalents at beginning of period	27,379	12,084
Cash and cash equivalents at end of period	26,670	23,649
Supplemental Disclosure of Cash Flow Information
Cash paid for income taxes	47	11
Supplemental Disclosure of Noncash Investing and Financing Information
Property and equipment purchased but not yet paid	108
Vesting of early exercised options	$ 1	$ 7