Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 4,926	$ 11,391
Short-term investments	18,183	9,475
Accounts receivable	77	107
Inventory	7,718	6,048
Prepaid expenses and other current assets	671	875
Total current assets	31,575	27,896
Property and equipment - net	673	535
Deferred tax assets	553	677
Right-of-use assets	1,131	1,058
Other assets	4,944	8,380
Total assets	38,876	38,546
Current liabilities:
Accounts payable	918	1,535
Accrued liabilities	1,562	2,012
Liability related to early exercised stock options	28	67
Customer deposits	940	1,371
Lease liabilities	704	549
Total current liabilities	4,152	5,534
Other liabilities	586	632
Total liabilities	4,738	6,166
Commitments and contingencies (Note 5)
Stockholders’ equity
Preferred stock, par value $0.0001 per share - 5,000,000 shares authorized as of September 30, 2020 and December 31, 2019; nil shares issued and outstanding as of September 30, 2020 and December 31, 2019
Common stock, par value $0.0001 per share - 75,000,000 shares authorized as of September 30, 2020 and December 31, 2019; 17,634,015 and 17,449,572 shares issued and outstanding as of September 30, 2020 and December 31, 2019, respectively	2	2
Additional paid-in-capital	22,149	20,928
Accumulated other comprehensive income (loss)	66	(15)
Retained earnings	11,921	11,465
Total stockholders’ equity	34,138	32,380
Total liabilities and stockholders’ equity	$ 38,876	$ 38,546