Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 49,510	$ 10,206
Short-term investments	86,740	49,295
Accounts receivable		786
Prepaid expenses and other current assets	3,250	3,574
Total current assets	139,500	63,861
Long-term investments		2,978
Property and equipment, net	146	28
Prepaid and other long-term assets	282
Total assets	139,928	66,867
Current liabilities:
Accounts payable	3,290	2,462
Accrued expenses and other current liabilities	6,254	3,559
Deferred revenue, current		1,796
Total current liabilities	9,544	7,817
Deferred revenue, long-term		6,735
Other non-current liabilities	7	22
Total liabilities	9,551	14,574
Commitments and contingencies (see Note 6)
Stockholders’ equity (deficit):
Preferred stock: $0.0001 par value; 20,000,000 shares and no shares authorized at December 31, 2018 and 2017, respectively; no shares issued and outstanding at December 31, 2018 and 2017, respectively
Common stock: $0.0001 par value; 300,000,000 shares and 55,000,000 shares authorized at December 31, 2018 and 2017, respectively; 23,233,184 and 5,298,593 shares issued and outstanding at December 31, 2018 and 2017, respectively	3	1
Additional paid-in capital	241,106	2,207
Accumulated other comprehensive loss	(96)	(51)
Accumulated deficit	(110,636)	(59,191)
Total stockholders’ equity (deficit)	130,377	(57,034)
Total liabilities, convertible preferred stock and stockholders’ equity (deficit)	$ 139,928	66,867
Series A Convertible Preferred Stock
Current liabilities:
Convertible preferred stock		14,183
Series B Convertible Preferred Stock
Current liabilities:
Convertible preferred stock		44,820
Series C Convertible Preferred Stock
Current liabilities:
Convertible preferred stock		$ 50,324