Consolidated Statements of Cash Flows - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Operating Activities
Net loss			$ (140,469,000)	$ (55,336,000)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities:
Loss (gain) from sale of SurgiBot assets, net	$ 0	$ 44,000	97,000	(11,915,000)
Goodwill and intangible assets impairment			86,881,000	0	$ 0
Depreciation			1,651,000	1,876,000
Amortization of intangible assets	2,558,000	2,674,000	7,754,000	8,244,000
Amortization of debt discount and debt issuance costs			1,437,000	575,000
Amortization of short-term investment discount			(328,000)	(51,000)
Interest expense on deferred consideration - MST acquisition			762,000	0
Stock-based compensation			9,727,000	6,694,000
Deferred tax benefit			(2,549,000)	(2,572,000)
Bad debt expense	1,600,000		1,630,000	0
Write down of inventory			761,000	0
Change in fair value of warrant liabilities	(614,000)	8,760,000	(3,036,000)	24,438,000
Change in fair value of contingent consideration	(11,647,000)	(1,358,000)	(9,689,000)	81,000
Loss on extinguishment of debt			0	1,400,000
Reversal of transfer fee accrual	0	(2,994,000)	0	(2,994,000)
Changes in operating assets and liabilities:
Accounts receivable			4,313,000	(4,262,000)
Interest receivable			3,000	28,000
Inventories			(14,141,000)	(1,276,000)
Other current and long term assets			(2,313,000)	27,000
Accounts payable			(914,000)	(903,000)
Accrued expenses			(1,439,000)	(56,000)
Deferred revenue			(867,000)	361,000
Other long term liabilities			1,613,000	0
Net cash and cash equivalents used in operating activities			(59,116,000)	(35,641,000)
Investing Activities
Purchase of short-term investments			(12,883,000)	(39,619,000)
Proceeds from maturities of short-term investments			65,000,000	0
Proceeds related to sale of SurgiBot assets, net			0	4,496,000
Purchase of property and equipment			(392,000)	(490,000)
Proceeds from sale of property and equipment			0	32,000
Net cash and cash equivalents provided by (used in) investing activities			51,725,000	(35,581,000)
Financing Activities
Payment of note payable			(15,000,000)	(15,305,000)
Proceeds from issuance of debt and warrants, net of issuance costs			(30,000)	18,828,000
Payment of contingent consideration			0	(395,000)
Proceeds from issuance of common stock and warrants, net of issuance costs			23,725,000	279,000
Taxes paid related to net share settlement of vesting of restricted stock units			(499,000)	(1,662,000)
Proceeds from issuance of common stock related to sale of SurgiBot assets			0	3,000,000
Proceeds from exercise of stock options and warrants			539,000	11,396,000
Net cash and cash equivalents provided by financing activities			8,735,000	16,141,000
Effect of exchange rate changes on cash and cash equivalents			(191,000)	(114,000)
Net increase (decrease) in cash, cash equivalents and restricted cash			1,153,000	(55,195,000)
Cash, cash equivalents and restricted cash, beginning of period			21,651,000	97,606,000	97,606,000
Cash, cash equivalents and restricted cash, end of period	22,804,000	$ 42,411,000	22,804,000	42,411,000	$ 21,651,000
Supplemental Disclosure for Cash Flow Information
Interest paid			2,073,000	1,135,000
Supplemental Schedule of Noncash Investing and Financing Activities
Transfer of inventories to property and equipment			478,000	2,160,000
Transfer of property and equipment to inventory				648,000
Reclass of warrant liability to common stock and additional paid-in capital			0	23,485,000
Cashless exercise of warrants				4,272,000
Issuance of common stock - MST acquisition	$ 6,600,000		$ 6,600,000	$ 0