Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current Assets
Cash and cash equivalents	$ 14,584	$ 64,315
Short-term investments	15,993
Accounts receivable, net	786	1,320
Inventories	2,777	2,097
Prepaid expenses and other current assets	1,860	1,501
Total current assets	36,000	69,233
Property and equipment, net	5,050	4,757
Operating lease right-of-use-assets	2,835
Other non-current assets	196	45
TOTAL ASSETS	44,081	74,035
Current Liabilities
Accounts payable	1,532	1,125
Accrued expenses	2,642	2,809
Current portion of deferred revenue	2,029	1,723
Current portion of equipment financing	293	293
Current portion of operating lease liabilities	318
Total current liabilities	6,814	5,950
Deferred revenue	1,232	767
Equipment financing	265	557
Operating lease liabilities	2,620
Other liabilities		56
Total liabilities	10,931	7,330
Commitments and contingencies (Note 14)
Stockholders’ Equity
Preferred stock, $0.0001 par value, 10,000,000 shares authorized at December 31, 2019 and 2018; none issued
Common stock, $0.0001 par value, 300,000,000 shares authorized at December 31, 2019 and 2018; 13,770,349 and 12,689,251 issued and outstanding at December 31, 2019 and 2018, respectively	1	1
Additional paid-in capital	150,280	126,925
Accumulated deficit	(117,157)	(60,221)
Accumulated other comprehensive income	26
Total stockholders’ equity	33,150	66,705
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 44,081	$ 74,035