Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenue	$ 24,102,000	$ 7,111,000	$ 1,519,000
Cost of revenue	16,171,000	6,727,000	1,069,000
Gross profit	7,931,000	384,000	450,000
Operating Expenses (Income)
Research and development	21,823,000	21,989,000	29,273,000
Sales and marketing	25,736,000	17,536,000	9,151,000
General and administrative	13,854,000	12,275,000	10,813,000
Amortization of intangible assets	10,868,000	7,858,000	6,967,000
Change in fair value of contingent consideration	(1,011,000)	2,026,000	482,000
Issuance costs for warrants		627,000
Inventory write-down related to restructuring			2,565,000
Restructuring and other charges			3,064,000
Goodwill impairment	0	0	61,784,000
Acquisition related costs	647,000
Gain from sale of SurgiBot assets, net	(11,840,000)
Reversal of transfer fee accrual	(2,994,000)
Total Operating Expenses (Income)	57,083,000	62,311,000	124,099,000
Operating Loss	(49,152,000)	(61,927,000)	(123,649,000)
Other (Expense) Income
Change in fair value of warrant liabilities	(14,320,000)	(83,734,000)
Interest income	1,400,000	308,000	132,000
Interest expense	(4,208,000)	(2,443,000)	(2,021,000)
Other income (expense)	1,126,000	(300,000)	35,000
Total Other (Expense) Income, net	(16,002,000)	(86,169,000)	(1,854,000)
Loss before income taxes	(65,154,000)	(148,096,000)	(125,503,000)
Income tax benefit	3,377,000	3,300,000	5,523,000
Net loss	(61,777,000)	(144,796,000)	(119,980,000)
Comprehensive loss
Foreign currency translation (loss) gain	(3,690,000)	10,797,000	(2,603,000)
Comprehensive loss	$ (65,467,000)	$ (133,999,000)	$ (122,583,000)
Net loss per share - basic and diluted	$ (0.30)	$ (0.97)	$ (1.07)
Weighted average common shares outstanding - basic and diluted	207,199	148,744	112,185