Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (33,487)	$ (33,080)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization for property and equipment	389	561
Net loss on disposal of property and equipment	0	1
Amortization of intangible assets	1,095	1,182
Reduction in the carrying amount of the right-of-use assets	973	742
(Gain) loss on disposal of intangible assets	(450)	48
Impairment of intangible assets	1,537	0
Stock-based compensation expense	5,685	5,320
Acquired in-process research and development	11,943	5,849
Change in fair value of investment in equity securities	(2,287)	355
Non-cash interest	0	1
Changes in operating assets and liabilities:
Accounts receivable	(2,785)	(2,643)
Inventories	3,822	(2,282)
Prepaid expenses and other assets	(434)	2,796
Accounts payable	(2,434)	3,877
Accrued liabilities and other liabilities	(1,398)	(1,152)
Deferred income	(23)	0
Net cash used in operating activities	(17,854)	(18,425)
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from disposal of intangible assets	1,700	0
Purchases of property and equipment	(367)	(390)
Loan to a related party	(10,033)	0
Receipt of repayment of loan from a related party	10,033	0
Cash paid for acquired in-process research and development	(11,678)	(5,849)
Cash paid to acquire equity securities in Black Belt Tx Limited	0	(2,250)
Cash paid to acquire debt securities in Black Belt Tx Limited	(83)	0
Cash paid to acquire equity securities in Juventas Cell Therapy Ltd		(11,788)
Receipt of government grants related to land use right	2,278	0
Net cash used in investing activities	(8,150)	(20,277)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from note payable	466
Repayment of notes payable		(1,500)
Stock issuance costs	(2,800)	(8)
Proceeds from issuance of common stock	45,099	0
Cash contribution from redeemable noncontrolling interest	0	20,000
Proceeds from exercise of stock options	3,874	114
Repurchase of stock options to satisfy tax withholding obligations	(251)	(12)
Proceeds from exercise of warrants	0	1,668
Payment of deferred offfering costs	0	(369)
Net cash provided by financing activities	46,388	19,893
Effect of exchange rate change on cash and cash equivalents	587	(2,155)
Net increase (decrease) in cash and cash equivalents	20,971	(20,964)
Cash and cash equivalents at beginning of period	53,621	84,205
Cash and cash equivalents at end of period	74,592	63,241
Supplemental disclosure of cash flow information:
Interest paid	0	30
Income taxes paid	$ 0	$ 0