Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 26,238	$ 25,941
Accounts receivable	155	236
Inventory	3,781	2,207
Prepaid expenses and other current assets	943	936
Total current assets	31,117	29,320
Property and equipment - net	509	611
Deferred tax assets	673	560
Lease assets	525
Other assets	210	215
Total assets	33,034	30,706
Current liabilities:
Accounts payable	1,321	1,063
Accrued liabilities	754	718
Liability related to early exercised stock options	102	136
Customer deposits	1,059	2
Total current liabilities	3,735	1,919
Lease liabilities	499
Other liabilities	198	156
Total liabilities	3,933	2,075
Commitments and contingencies (Note 5)
Stockholders’ equity
Preferred stock, par value $0.0001 per share - 5,000,000 shares authorized as of June 30, 2019 and December 31, 2018; nil shares issued and outstanding as of June 30, 2019 and December 31, 2018
Common stock, par value $0.0001 per share - 75,000,000 shares authorized as of June 30, 2019 and December 31, 2018; 17,255,610 and 17,130,507 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively	2	2
Additional paid-in-capital	20,111	19,358
Retained earnings	8,988	9,271
Total stockholders’ equity	29,101	28,631
Total liabilities and stockholders’ equity	$ 33,034	$ 30,706