Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities
Net loss	$ (34,016)	$ (22,644)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	412	341
Stock-based compensation	3,859	2,242
Changes in operating assets and liabilities:
Prepaid expenses, deposits and other	336	677
Accounts payable and accrued expenses	3,720	1,192
Net cash used in operating activities	(24,847)	(16,959)
Investing activities
Purchases of equipment	(551)	(400)
Net cash used in investing activities	(551)	(400)
Financing activities
Shares retained for withholding tax payments on stock-based awards	(451)	(176)
Net cash provided by financing activities	71,064	10,537
Increase (decrease) in cash and cash equivalents	45,666	(6,822)
Cash and cash equivalents at beginning of the period	35,041	51,059
Cash and cash equivalents at end of the period	80,707	44,237
Consolidated entity excluding, related party
Changes in operating assets and liabilities:
Accounts receivable	(7)	182
Financing activities
Proceeds from issuance of common stock, net of issuance cost	63,941	10,713
Healios
Changes in operating assets and liabilities:
Accounts receivable	849	1,820
Deferred revenue - Healios	0	(672)
Advances and deposits from Healios	0	(97)
Financing activities
Proceeds from issuance of common stock, net of issuance cost	534	0
Proceeds from exercise of warrant	$ 7,040	$ 0