Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019		Jun. 30, 2018
Operating activities
Net loss	$ (51,611)		$ (39,310)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	1,353		1,343
Amortization of deferred financing costs	282		59
Amortization of deferred compensation for services	154		101
Amortization of premium on investment securities	(537)		(256)
Non-cash lease expense	891
Stock-based compensation	3,845		5,028
Change in derivative liabilities	61
Non-cash interest associated with debt discount accretion	231		54
Changes in operating assets and liabilities:
Accounts receivable and unbilled license revenue	5,068		10,766
Prepaid expenses and other assets	(56)		1,192
Accounts payable	(887)		(706)
Accrued compensation and benefits	(372)		(1,026)
Accrued and other liabilities	(3,155)		(2,064)
Net cash used in operating activities	(44,733)		(24,819)
Investing activities
Proceeds from maturities of investments	86,454		56,050
Sales and redemptions of investments			850
Purchases of investments	(30,857)		(119,021)
Purchases of property and equipment	(211)		(55)
Net cash provided by (used in) investing activities	55,386		(62,176)
Financing activities
Proceeds from loan payable, net of issuance costs			49,292
Proceeds from underwritten public offering, net of issuance costs			53,770
Issuance of common stock upon exercise of options	7
Proceeds from issuance of common stock under stock plans	198		301
Net cash provided by financing activities	205		103,363
Net increase (decrease) in cash and cash equivalents	10,858		16,368
Cash and cash equivalents at beginning of period	78,768	[1]	75,383
Cash and cash equivalents at end of period	$ 89,626		91,751
Supplementary disclosure of non-cash financing information:
Issuance of derivative in connection with issuance of loan payable			$ 546

[1] Derived from the audited consolidated financial statements included in the Company’s Annual Report on Form 10K for the year ended December 31, 2018.