CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	SafeOp Surgical, Inc. Milestone 1 and Milestone 2	Series A Convertible Preferred Stock	Additional paid-in capital	Additional paid-in capital SafeOp Surgical, Inc. Milestone 1 and Milestone 2	Shareholder note receivable	Treasury stock	Accumulated other comprehensive income	Accumulated deficit	Accumulated deficit Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Common Stock SafeOp Surgical, Inc.	Common Stock SafeOp Surgical, Inc. Milestone 1 and Milestone 2
Balance at Dec. 31, 2018	$ 17,574				$ 523,525		$ (5,000)	$ (97)	$ 1,064	$ (501,922)		$ 4
Balance, shares at Dec. 31, 2018				4,000								43,368,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	10,294				10,294
Common stock issued for conversion of Series A preferred stock, shares				(4,000)								1,954,000
Recognition of beneficial conversion feature - SafeOp Convertible Notes	242				242
Distributor equity incentives	322				322
Distributor equity incentives, shares												75,000
Common stock issued for warrant exercises	1,668				1,668
Common stock issued for warrant exercises, shares												757,000
Common stock issued for employee stock purchase plan and stock option exercises	1,522				1,522
Common stock issued for employee stock purchase plan and stock option exercises, shares												477,000
Common stock issued for vesting of performance and restricted stock units and restricted stock awards, net of tax liability	(1,414)				(1,414)
Common stock issued for vesting of performance and restricted stock units and restricted stock awards, net of tax liability, shares												1,347,000
Issuance of common stock warrants, net	13,664				13,664
Issuance of common stock for public offering, net of offering costs	53,848				53,846							$ 2
Issuance of common stock for public offering, net of offering costs, shares												12,535,000
Issuance of common stock for acquisition			$ 2,889			$ 2,889
Issuance of common stock for acquisition, shares													886,843	887,000
Foreign currency translation adjustments	24								24
Net loss	(57,002)									(57,002)
Balance at Dec. 31, 2019	$ 43,631	$ (81)			606,558		(5,000)	(97)	1,088	(558,924)	$ (81)	$ 6
Balance, shares at Dec. 31, 2019												61,400,000
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201908Member
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 15,730				15,730
Common stock issued for conversion of Series A preferred stock, shares												39,000
Distributor equity incentives	521				521
Common stock issued for warrant exercises	2,368				2,368
Common stock issued for warrant exercises, shares												1,907,000
Common stock issued for employee stock purchase plan and stock option exercises	1,970				1,970
Common stock issued for employee stock purchase plan and stock option exercises, shares												665,000
Common stock issued for vesting of performance and restricted stock units and restricted stock awards, net of tax liability	(983)				(983)
Common stock issued for vesting of performance and restricted stock units and restricted stock awards, net of tax liability, shares												2,238,000
Issuance of common stock warrants, net	2,974				2,974
Issuance of common stock for public offering, net of offering costs	107,698				107,696							$ 2
Issuance of common stock for public offering, net of offering costs, shares												13,143,000
Shareholder note receivable	1,000						1,000
Issuance of common stock for other services	123				123
Issuance of common stock for other services, shares												12,000
Issuance of common stock for prepayment of debt	33,807				33,807
Issuance of common stock for prepayment of debt, shares												2,700,000
Foreign currency translation adjustments	116								116
Net loss	(78,994)									(78,994)
Balance at Dec. 31, 2020	$ 129,880				$ 770,764		$ (4,000)	$ (97)	$ 1,204	$ (637,999)		$ 8
Balance, shares at Dec. 31, 2020												82,104,000