Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
CURRENT ASSETS
Cash and cash equivalents	$ 286,649	$ 171,160
Short-term investments	224,621	118,955
Prepaid expenses and other current assets	7,171	6,487
Total current assets	518,441	296,602
Property and equipment, net	13,967	14,755
Intangible assets	32,334	0
Operating lease right of use assets	25,961	26,531
Restricted cash	730	730
Other non-current assets	1,494	1,669
TOTAL ASSETS	592,927	340,287
CURRENT LIABILITIES
Accounts payable	8,709	8,010
Accruals and other current liabilities	16,178	18,636
Deferred revenue, current portion	10,079	7,911
Operating lease liabilities, current portion	3,627	3,470
Derivative liability	3,042	2,952
Derivative liability	41,635	40,979
Convertible senior notes	171,305	0
Deferred revenue, net of current portion	46,722	47,948
Operating lease liabilities, net of current portion	24,890	25,870
TOTAL LIABILITIES	284,552	114,797
Commitments and Contingencies (Note 10)
STOCKHOLDERS’ EQUITY
Convertible preferred stock, par value $0.001 per share — 5,000,000 shares authorized, and no shares issued and outstanding as of March 31, 2020 and December 31, 2019	0	0
Common stock, par value $0.001 per share — 95,000,000 shares authorized both as of March 31, 2020 and December 31, 2019; 57,026,154 and 52,374,735 shares issued and outstanding as of March 31, 2020 and December 31, 2019, respectively	57	52
Additional paid-in capital	1,213,931	1,069,639
Accumulated other comprehensive income	524	3
Accumulated deficit	(906,137)	(844,204)
TOTAL STOCKHOLDERS’ EQUITY	308,375	225,490
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 592,927	$ 340,287