Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Operating Activities
Net loss	$ (22,525)	$ (882)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities:
Loss (gain) from sale of SurgiBot assets, net	97	(11,996)
Depreciation	563	660
Amortization of intangible assets	2,611	2,827
Amortization of debt discount and debt issuance costs	330	274
Amortization of short-term investment discount	(220)
Interest expense on deferred consideration - MST acquisition	204
Stock-based compensation	2,981	1,834
Deferred tax benefit	(610)	(890)
Change in fair value of warrant liabilities	106	(1,829)
Change in fair value of contingent consideration	998	627
Changes in operating assets and liabilities:
Accounts receivable	(129)	(296)
Interest receivable	(8)	(21)
Inventories	(4,621)	(604)
Other current and long term assets	(2,655)	1,171
Accounts payable	286	(217)
Accrued expenses	(2,518)	(2,871)
Deferred revenue	(197)	(86)
Other long term liabilities	1,112
Net cash and cash equivalents used in operating activities	(24,195)	(12,299)
Investing Activities
Purchase of short-term investments	(10,894)
Proceeds from maturities of short-term investments	40,000
Proceeds related to sale of SurgiBot assets, net		4,496
Purchase of property and equipment	(118)	(218)
Proceeds from sale of property and equipment		17
Net cash and cash equivalents provided by investing activities	28,988	4,295
Financing Activities
Proceeds from issuance of common stock and warrants, net of issuance costs		11
Taxes paid related to net share settlement of vesting of restricted stock units	(499)
Proceeds from issuance of common stock related to sale of SurgiBot assets		3,000
Proceeds from exercise of stock options and warrants	236	1,712
Net cash and cash equivalents (used in) provided by financing activities	(263)	4,723
Effect of exchange rate changes on cash and cash equivalents	(58)	88
Net increase (decrease) in cash, cash equivalents and restricted cash	4,472	(3,193)
Cash, cash equivalents and restricted cash, beginning of period	21,651	97,606	$ 97,606
Cash, cash equivalents and restricted cash, end of period	26,123	94,413	$ 21,651
Supplemental Disclosure for Cash Flow Information
Interest paid	750	304
Supplemental Schedule of Noncash Investing and Financing Activities
Transfer of inventories to property and equipment	$ 86	71
Reclass of warrant liability to common stock and additional paid-in capital		$ 516