CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net loss	$ (28,975)	$ (2,294)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	6,789	7,481
Stock-based compensation	5,304	3,981
Amortization of debt discount and debt issuance costs	2,087	2,761
Provision (recovery) for doubtful accounts	164	(164)
(Recovery) provision for excess and obsolete inventory	4,743	2,542
Deferred income tax benefit	(1,405)	(36)
Gain on settlement	(6,168)
Gain on sale of assets		(856)
Loss on extinguishment of debt	590
Gain from change in estimated fair value of warrants		(12,044)
Loss on disposal of instruments	130	281
Accretion to contingent consideration	846
Changes in operating assets and liabilities:
Accounts receivable, net	(396)	4,153
Inventories, net	(6,024)	258
Prepaid expenses and other current assets	(268)	3,080
Other assets	(90)	348
Accrued expenses and other	1,677	(6,327)
Accounts payable	16	(2,592)
Deferred revenue	(261)	223
Other long-term liabilities	(4,367)	(9,524)
Net cash used in operating activities	(25,608)	(8,729)
Investing activities:
Purchases of property and equipment	(6,514)	(7,596)
Cash paid for acquisition of SafeOp Surgical, Inc.	(15,103)
Cash paid for acquisition of intangible assets	(400)
Cash received from sale of equipment	348	1,101
Net cash used in investing activities	(21,669)	(6,495)
Financing activities:
Proceeds from sale of stock, net	51,902	24,386
Borrowings under lines of credit	90,459	96,244
Repayments under lines of credit	(89,993)	(98,443)
Principal payments on capital lease obligations	(96)	(572)
Proceeds from issuance of term debt, net	34,077
Principal payments on term loan and notes payable	(32,464)	(3,794)
Net cash provided by financing activities	53,885	17,821
Effect of exchange rate changes on cash	(20)	276
Net increase in cash	6,588	2,873
Cash at beginning of year	22,466	19,593
Cash at end of year	29,054	22,466
Supplemental disclosure of cash flow information:
Cash paid for interest	5,141	4,695
Cash paid for income taxes	134	107
Supplemental disclosure of noncash investing and financing activities:
Issuance of warrants upon execution of term loan	1,708
Purchases of property and equipment in accounts payable	940	436
Reclassification of warrant liabilities to equity		14,355
Common stock issued for acquisition of intangible assets		473
Capital lease additions included in property and equipment		156
Subscription receivable		$ 300
SafeOp Surgical, Inc.
Adjustments to reconcile net loss to net cash used in operating activities:
Accretion to contingent consideration	800
Supplemental disclosure of noncash investing and financing activities:
Common stock and warrants issued for the acquisition of SafeOp	12,529
Common stock issued for achievement of SafeOp contingent consideration	$ 1,446