Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 12,084	$ 11,391
Short-term investments	17,567	9,475
Accounts receivable	118	107
Inventory	8,901	6,048
Prepaid expenses and other current assets	614	875
Total current assets	39,284	27,896
Property and equipment - net	647	535
Deferred tax assets	588	677
Right-of-use assets	959	1,058
Other assets	1,741	8,380
Total assets	43,219	38,546
Current liabilities:
Accounts payable	1,457	1,535
Accrued liabilities	2,523	2,012
Liability related to early exercised stock options	19	67
Customer deposits	735	1,371
Lease liabilities	720	549
Total current liabilities	5,454	5,534
Other liabilities	392	632
Total liabilities	5,846	6,166
Commitments and contingencies (Note 5)
Stockholders’ equity
Preferred stock, par value $0.0001 per share - 5,000,000 shares authorized as of December 31, 2020 and 2019; nil shares issued and outstanding as of December 31, 2020 and 2019.
Common stock, par value $0.0001 per share - 75,000,000 shares authorized as of December 31, 2020 and 2019; 17,690,062 and 17,449,572 shares issued and outstanding as of December 31, 2020 and 2019, respectively	2	2
Additional paid-in capital	22,523	20,928
Accumulated other comprehensive income (loss)	41	(15)
Retained earnings	14,807	11,465
Total stockholders’ equity	37,373	32,380
Total liabilities and stockholders’ equity	$ 43,219	$ 38,546