Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Revision of Prior Period, Accounting Standards Update, Adjustment	Common Stock	Additional Paid In Capital	Accumulated Other Comprehensive Gain	Noncontrolling Interest	Accumulated Deficit	Accumulated Deficit Revision of Prior Period, Accounting Standards Update, Adjustment
Beginning Balance at Dec. 31, 2019	$ 571,039	$ 93	$ 12	$ 935,834	$ 671		$ (365,478)	$ 93
Beginning Balance, Shares at Dec. 31, 2019			125,238,142
Accounting Standards Update [Extensible Enumeration]	us-gaap:AccountingStandardsUpdate201602Member
Issuance of common stock upon public offering, after deducting underwriters' discounts and net offering costs payable by us	$ 271,839		$ 1	271,838
Issuance of common stock upon public offering, after deducting underwriters' discounts and net offering costs payable by us, Shares			7,200,000
Issuance of common stock for cash upon exercise of stock options	15,459			15,459
Issuance of common stock for cash upon exercise of stock options, Shares			3,949,614
Vesting of restricted stock units			4,500
Common stock option and restricted stock unit share-based compensation	17,518			17,518
Other comprehensive income (loss)	756				756
Net loss	(101,657)						(101,657)
Ending Balance at Sep. 30, 2020	775,047		$ 13	1,240,649	1,427		(467,042)
Ending Balance, Shares at Sep. 30, 2020			136,392,256
Beginning Balance at Jun. 30, 2020	529,939		$ 12	958,097	2,153		(430,323)
Beginning Balance, Shares at Jun. 30, 2020			128,233,842
Issuance of common stock upon public offering, after deducting underwriters' discounts and net offering costs payable by us	271,839		$ 1	271,838
Issuance of common stock upon public offering, after deducting underwriters' discounts and net offering costs payable by us, Shares			7,200,000
Issuance of common stock for cash upon exercise of stock options	4,244			4,244
Issuance of common stock for cash upon exercise of stock options, Shares			958,414
Common stock option and restricted stock unit share-based compensation	6,470			6,470
Other comprehensive income (loss)	(726)				(726)
Net loss	(36,719)						(36,719)
Ending Balance at Sep. 30, 2020	775,047		$ 13	1,240,649	1,427		(467,042)
Ending Balance, Shares at Sep. 30, 2020			136,392,256
Beginning Balance at Dec. 31, 2020	743,266		$ 14	1,253,971	893		(511,612)
Beginning Balance, Shares at Dec. 31, 2020			137,646,896
Issuance of common stock upon exercise of common stock warrants, Shares			54,162
Issuance of common stock for cash upon exercise of stock options	$ 23,299			23,299
Issuance of common stock for cash upon exercise of stock options, Shares	3,310,804		3,310,804
Vesting of restricted stock units			15,625
Common stock option and restricted stock unit share-based compensation	$ 31,376			31,376
Capital contributions for Spin Technologies, Inc.	429			300		$ 129
Other comprehensive income (loss)	(886)				(886)
Net loss	(145,941)					(95)	(145,846)
Ending Balance at Sep. 30, 2021	651,543		$ 14	1,308,946	7	34	(657,458)
Ending Balance, Shares at Sep. 30, 2021			141,027,487
Beginning Balance at Jun. 30, 2021	693,310		$ 14	1,294,506	216	129	(601,555)
Beginning Balance, Shares at Jun. 30, 2021			140,663,755
Issuance of common stock for cash upon exercise of stock options	2,797			2,797
Issuance of common stock for cash upon exercise of stock options, Shares			360,607
Vesting of restricted stock units			3,125
Common stock option and restricted stock unit share-based compensation	11,643			11,643
Other comprehensive income (loss)	(209)				(209)
Net loss	(55,998)					(95)	(55,903)
Ending Balance at Sep. 30, 2021	$ 651,543		$ 14	$ 1,308,946	$ 7	$ 34	$ (657,458)
Ending Balance, Shares at Sep. 30, 2021			141,027,487