Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 25,941	$ 21,536
Accounts receivable	236	93
Inventory	2,207	2,847
Prepaid expenses and other current assets	936	978
Total current assets	29,320	25,454
Property and equipment - net	611	325
Deferred tax assets	560	652
Other assets	215	161
Total assets	30,706	26,592
Current liabilities:
Accounts payable	1,063	760
Accrued liabilities	718	573
Liability related to early exercised stock options	136	152
Customer deposits	2	6
Total current liabilities	1,919	1,491
Other liabilities	156	133
Total liabilities	2,075	1,624
Commitments and contingencies (Note 5)
Stockholders’ equity
Preferred stock, par value $0.0001 per share - 5,000,000 shares authorized as of December 31, 2018 and 2017; nil shares issued and outstanding as of December 31, 2018 and 2017
Common stock, par value $0.0001 per share - 75,000,000 shares authorized as of December 31, 2018 and 2017; 17,130,507 and 16,752,171 shares issued and outstanding as of December 31, 2018 and 2017, respectively	2	2
Additional paid-in-capital	19,358	17,580
Retained earnings	9,271	7,386
Total stockholders’ equity	28,631	24,968
Total liabilities and stockholders’ equity	$ 30,706	$ 26,592