CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	SafeOp Surgical, Inc.	SafeOp Surgical, Inc. Milestone 1 and Milestone 2	Series A Convertible Preferred Stock	Series B Convertible Preferred Stock	Common stock	Common stock SafeOp Surgical, Inc.	Common stock SafeOp Surgical, Inc. Milestone 1 and Milestone 2	Additional paid-in capital	Additional paid-in capital SafeOp Surgical, Inc.	Additional paid-in capital SafeOp Surgical, Inc. Milestone 1 and Milestone 2	Shareholder note receivable	Treasury stock	Accumulated other comprehensive income (loss)	Accumulated deficit
Balance at Dec. 31, 2017	$ (26,658)					$ 2			$ 436,803			$ (5,000)	$ (97)	$ 1,093	$ (459,459)
Balance, shares at Dec. 31, 2017				5,000		19,857,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	5,649								5,649
Common stock issued for conversion of Series A preferred stock, shares				(1,000)		14,986,000
Issuance of warrants in conjunction with Squadron Term Loan	1,708								1,708
Issuance and conversion of preferred stock into common stock, net of offering costs	42,610					$ 2			42,608
Recognition of beneficial conversion feature -Series B Preferred Stock and SaleOp Convertible Notes									13,488						(13,488)
Common stock issued for employee stock purchase plan and stock option exercises	666								666
Common stock issued for employee stock purchase plan and stock option exercises, shares						258,000
Common stock issued for vesting of restricted stock awards, net of shares repurchased for tax liability, shares						248,000
Common stock issued for warrant exercises, net of issuance costs	8,628								8,628
Common stock issued for warrant exercises, net of issuance costs. shares						4,311,000
Issuance of common stock and warrants for the acquisition of SafeOp		$ 12,529								$ 12,529
Issuance of common stock and warrants for the acquisition of SafeOp, shares							$ 3,265
Issuance of common stock for acquisition			$ 1,446								$ 1,446
Issuance of common stock for acquisition, shares							443,421	443,000
Foreign currency translation adjustments	(29)													(29)
Net loss	(28,975)			$ 0	$ 0										(28,975)
Balance at Dec. 31, 2018	17,574					$ 4			523,525			(5,000)	(97)	1,064	(501,922)
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				$ (4)
Common stock issued for conversion of Series A preferred stock, shares						1,954,000
Recognition of beneficial conversion feature -Series B Preferred Stock and SaleOp Convertible Notes	242								242
Distributor equity incentives	322								322
Distributor equity incentives, shares						75,000
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 warrant exercises, net of issuance costs	1,668								1,668
Common stock issued for warrant exercises, net of issuance costs. shares						757,000
Common stock issued for vesting of performances 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	13,664								13,664
Issuance of common stock for public offering, net of offering costs	53,848					$ 2			53,846
Issuance of stock 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					$ 6			$ 606,558			$ (5,000)	$ (97)	$ 1,088	$ (558,924)
Balance, shares at Dec. 31, 2019						61,400,000