Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities
Net loss	$ (144,796,000)	$ (119,980,000)	$ (46,948,000)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities:
Depreciation	2,486,000	1,942,000	1,248,000
Amortization of intangible assets	7,858,000	6,967,000	2,185,000
Amortization of debt discount and debt issuance costs	510,000	177,000	142,000
Stock-based compensation	7,078,000	5,033,000	3,311,000
Non-employee warrant awards	838,000
Common stock issued for services		116,000
Inventory write-down related to restructuring		2,565,000
Loss on disposal of property			34,000
Non-cash restructuring and other charges		2,556,000
Goodwill impairment	0	61,784,000	0
Deferred tax benefit	(3,300,000)	(5,562,000)	(1,024,000)
Loss on extinguishment of debt	308,000
Change in fair value of warrant liabilities	83,734,000
Change in fair value of contingent consideration	2,026,000	482,000	(400,000)
Changes in operating assets and liabilities, net of effect of acquisition:
Accounts receivable	(381,000)	(1,041,000)	133,000
Interest receivable	23,000	(6,000)	(5,000)
Inventories	(2,981,000)	(6,647,000)	(4,630,000)
Other current and long term assets	(3,348,000)	(1,528,000)	728,000
Accounts payable	(531,000)	(356,000)	1,096,000
Accrued expenses	2,093,000	1,112,000	5,371,000
Deferred revenue	1,088,000
Deferred gain on sale of SurgiBot assets	7,500,000
Net cash and cash equivalents used in operating activities	(39,795,000)	(52,386,000)	(38,759,000)
Investing Activities
Payment for acquisition of a business			(25,000,000)
Purchase of property and equipment	(1,566,000)	(1,361,000)	(1,234,000)
Purchase of intellectual property	(425,000)
Net cash and cash equivalents used in investing activities	(1,991,000)	(1,361,000)	(26,234,000)
Financing Activities
Payment of debt	(13,343,000)	(6,902,000)
Proceeds from issuance of debt and warrants, net of issuance costs	13,005,000		9,887,000
Payment of contingent consideration	(7,181,000)	(1,182,000)
Proceeds from issuance of common stock and warrants, net of issuance costs	77,579,000	58,029,000	58,331,000
Taxes paid related to net share settlement of vesting of restricted stock units	(168,000)	(168,000)	(73,000)
Proceeds from exercise of stock options and warrants	34,479,000	166,000	259,000
Net cash and cash equivalents provided by financing activities	104,371,000	49,943,000	68,404,000
Effect of exchange rate changes on cash and cash equivalents	431,000	(55,000)	22,000
Net increase (decrease) in cash, cash equivalents and restricted cash	63,016,000	(3,859,000)	3,433,000
Cash, cash equivalents and restricted cash, beginning of period	34,590,000	38,449,000	35,016,000
Cash, cash equivalents and restricted cash, end of period	97,606,000	34,590,000	38,449,000
Supplemental Disclosure for Cash Flow Information
Interest paid	899,000	1,289,000	973,000
Supplemental Schedule of Noncash Investing and Financing Activities
Transfer of inventory to property and equipment	1,258,000	$ 3,198,000
Issuance of common stock as contingent consideration	5,227,000
Relative fair value of warrants issued with debt	300,000		97,000
Reclass of warrant liability to common stock and additional paid in capital	78,359,000
Transfer of in-process research and development to intellectual property	17,913,000
Cashless exercise of warrants	$ 149,000
Issuance of common stock warrants			97,000
Contingent consideration related to acquisition			23,900,000
Issuance of common stock related to acquisition			$ 43,677,000