Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 24,846	$ 21,536
Accounts receivable	348	93
Inventory	2,509	2,847
Prepaid expenses and other current assets	1,009	978
Total current assets	28,712	25,454
Property and equipment - net	452	325
Deferred tax assets	721	652
Other assets	213	161
Total assets	30,098	26,592
Current liabilities:
Accounts payable	1,038	760
Accrued liabilities	974	573
Liability related to early exercised stock options	154	152
Customer deposits	197	6
Total current liabilities	2,363	1,491
Other liabilities	150	133
Total liabilities	2,513	1,624
Commitments and contingencies (Note 5)
Stockholders’ equity
Preferred stock, par value $0.0001 per share - 5,000,000 shares authorized as of September 30, 2018 and December 31, 2017; nil shares issued and outstanding as of September 30, 2018 and December 31, 2017
Common stock, par value $0.0001 per share - 75,000,000 shares authorized as of September 30, 2018 and December 31, 2017; 17,074,636 and 16,752,171 shares issued and outstanding as of September 30, 2018 and December 31, 2017, respectively	2	2
Additional paid-in-capital	18,959	17,580
Retained earnings	8,624	7,386
Total stockholders’ equity	27,585	24,968
Total liabilities and stockholders’ equity	$ 30,098	$ 26,592