Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating Activities
Net loss	$ (35,130)	$ (30,127)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities:
Gain from sale of SurgiBot assets, net	(11,959)
Depreciation	1,277	1,142
Amortization of intangible assets	5,570	3,323
Amortization of debt discount and debt issuance costs	495	43
Stock-based compensation	4,204	3,679
Deferred tax benefit	(1,799)	(1,580)
Loss on extinguishment of debt	1,400	308
Change in fair value of warrant liabilities	15,678	2,326
Change in fair value of contingent consideration	1,439	453
Changes in operating assets and liabilities:
Accounts receivable	(762)	(487)
Interest receivable	(24)	39
Inventories	(1,560)	(862)
Other current and long term assets	1,905	(1,473)
Accounts payable	404	(1,909)
Accrued expenses	(359)	(390)
Deferred revenue	31
Net cash and cash equivalents used in operating activities	(19,190)	(25,515)
Investing Activities
Proceeds related to sale of SurgiBot assets, net	4,496
Purchase of property and equipment	(358)	(1,397)
Purchase of intellectual property		(398)
Proceeds from sale of property and equipment	32
Net cash and cash equivalents provided by (used in) investing activities	4,170	(1,795)
Financing Activities
Payment of notes payable	(15,305)	(13,343)
Proceeds from issuance of debt and warrants, net of issuance costs	18,870	13,196
Payment of contingent consideration	(395)
Proceeds from issuance of common stock and warrants, net of issuance costs	2	29,193
Taxes paid related to net share settlement of vesting of restricted stock units		(168)
Proceeds from issuance of common stock related to sale of SurgiBot assets	3,000
Proceeds from exercise of stock options and warrants	9,813
Net cash and cash equivalents provided by financing activities	15,985	28,878
Effect of exchange rate changes on cash and cash equivalents	(78)	2
Net increase in cash, cash equivalents and restricted cash	887	1,570
Cash, cash equivalents and restricted cash, beginning of period	97,606	34,590
Cash, cash equivalents and restricted cash, end of period	98,493	36,160
Supplemental Disclosure for Cash Flow Information
Interest paid	599	368
Supplemental Schedule of Noncash Investing and Financing Activities
Transfer of inventories to property and equipment	1,055
Issuance of common stock as contingent consideration		5,227
Relative fair value of warrants issued with debt		$ 300
Reclass of warrant liability to common stock and additional paid-in capital	$ 7,060