Stock-Benefit Plans and Equity Transactions - Summary of All Outstanding Warrants for Common Stock (Details)	6 Months Ended
	Jun. 30, 2021 $ / shares shares
Class Of Warrant Or Right [Line Items]
Number of Warrants	20,525,288
2017 PIPE Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	2,587,000
Strike Price | $ / shares	$ 2.00
Expiration	June 2022
2018 PIPE Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	8,538,569
Strike Price | $ / shares	$ 3.50
Expiration	May 2023
SafeOp Surgical Merger Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	1,194,943
Strike Price | $ / shares	$ 3.50
Expiration	May 2023
2018 Squadron Medical Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	845,000
Strike Price | $ / shares	$ 3.15
Expiration	May 2027
2019 Squadron Medical Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	4,838,710
Strike Price | $ / shares	$ 2.17
Expiration	May 2027
2020 Squadron Medical Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	1,075,820
Strike Price | $ / shares	$ 4.88
Expiration	May 2027
Executive Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	1,327,434
Strike Price | $ / shares	$ 5.00
Expiration	December 2022
Other Warrants
Class Of Warrant Or Right [Line Items]
Number of Warrants	117,812	[1]
Strike Price | $ / shares	$ 2.87	[1]
Expiration	Various through May 2023	[1]

[1] Weighted-average strike price.