Acquisition of SafeOp Surgical, Inc. - Additional Information (Details) - USD ($)			3 Months Ended		9 Months Ended
	Mar. 09, 2018	Mar. 08, 2018	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2018	Mar. 31, 2018
Business Acquisition [Line Items]
Accretion to contingent consideration					$ 646,000
Developed SSEP Technology
Business Acquisition [Line Items]
Useful lives					12 years
SafeOp Surgical, Inc.
Business Acquisition [Line Items]
Business acquisition date	Mar. 09, 2018
Increase in net loss due to operating expenses			$ 1,600,000		$ 3,000,000
Cash paid and payable	$ 15,100,000				15,103,000
Cash payment for acquisition					15,100,000
Stock issued for acquisition, value		$ 9,800,000
Closing share price		$ 3.30
Convertible notes issued	$ 3,000,000
Convertible note convertible to common stock	987,578
Number of warrants issued	2,200,000
Exercise price of warrants per share	$ 3.50
Intangible assets						$ 21,600,000
Transaction costs			1,500,000		1,500,000
Additional shares of common stock value issuable subject to performance milestones					4,300,000
Accretion to contingent consideration			500,000		600,000
SafeOp Surgical, Inc. | Ten Days After Submission of an Application for Regulatory Clearance
Business Acquisition [Line Items]
Additional shares of common stock value issuable subject to performance milestones					1,400,000
SafeOp Surgical, Inc. | Ten Days After Receipt of Clearance from Regulatory Authority
Business Acquisition [Line Items]
Additional shares of common stock value issuable subject to performance milestones					2,900,000
SafeOp Surgical, Inc. | EPAD Tradename
Business Acquisition [Line Items]
Intangible assets			60,000		$ 60,000
Useful lives					1 year
SafeOp Surgical, Inc. | Developed SSEP Technology
Business Acquisition [Line Items]
Intangible assets			$ 13,100,000		$ 13,100,000
Useful lives					20 years
SafeOp Surgical, Inc. | Common Stock
Business Acquisition [Line Items]
Stock issued for acquisition	3,265,132	2,975,209	174,302	115,621
SafeOp Surgical, Inc. | Common Stock | Ten Days After Submission of an Application for Regulatory Clearance
Business Acquisition [Line Items]
Stock issued for acquisition			443,421