Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 71,064	$ 98,426
Short-term investments	185,480	77,277
Prepaid expenses and other current assets	2,321	1,141
Amounts owed by a related party	83	25
Total current assets	258,948	176,869
Long-term investments	3,181
Property and equipment, net	11,107	11,230
Equity investment in related party	1,202	682
Restricted cash	203	203
Other long-term assets	284	1,502
Total assets	274,925	190,486
Current liabilities:
Accounts payable	3,102	3,820
Accrued liabilities	6,023	3,137
Deferred revenue, current	6,250	5,000
Other current liabilities	1,560	769
Total current liabilities	16,935	12,726
Deferred revenue, noncurrent	16,984	18,587
Deferred rent	4,272	4,740
Other long-term liabilities	1,792	565
Total liabilities	39,983	36,618
Commitments (Note 12)
Convertible preferred stock, $0.0001 par value, no shares and 120,958,867 shares authorized as of December 31, 2018 and 2017, respectively; no shares and 30,459,574 shares issued and outstanding as of December 31, 2018 and 2017, respectively	0	226,196
Stockholders’ equity (deficit):
Preferred stock, $0.0001 par value, 10,000,000 shares authorized as of December 31, 2018; no shares issued and outstanding	0
Common stock, $0.0001 par value, 400,000,000 and 153,993,227 shares authorized as of December 31, 2018 and 2017, respectively; 44,537,946 and 4,090,898 shares issued and outstanding as of December 31, 2018 and 2017, respectively	4
Additional paid-in capital	357,873	948
Accumulated deficit	(122,828)	(73,234)
Accumulated other comprehensive loss	(107)	(42)
Total stockholders’ equity (deficit)	234,942	(72,328)
Total liabilities, convertible preferred stock and stockholders’ equity	$ 274,925	$ 190,486