Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 23,796	$ 21,536
Accounts receivable	155	93
Inventory	2,067	2,847
Prepaid expenses and other current assets	805	978
Total current assets	26,823	25,454
Property and equipment - net	395	325
Deferred tax assets	887	652
Other assets	281	161
Total assets	28,386	26,592
Current liabilities:
Accounts payable	1,083	760
Accrued liabilities	593	573
Liability related to early exercised stock options	173	152
Customer deposits	29	6
Total current liabilities	1,878	1,491
Other liabilities	143	133
Total liabilities	2,021	1,624
Commitments and contingencies (Note 5)
Stockholders’ equity
Preferred stock, par value $0.0001 per share - 5,000,000 shares authorized as of June 30, 2018 and December 31, 2017; nil shares issued and outstanding as of June 30, 2018 and December 31, 2017
Common stock, par value $0.0001 per share - 75,000,000 shares authorized as of June 30, 2018 and December 31, 2017; 16,999,177 and 16,752,171 shares issued and outstanding as of June 30, 2018 and December 31, 2017, respectively	2	2
Additional paid-in-capital	18,303	17,580
Retained earnings	8,060	7,386
Total stockholders’ equity	26,365	24,968
Total liabilities and stockholders’ equity	$ 28,386	$ 26,592