Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income (loss)	$ (23,982)	$ 27,193	$ 18,722
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	13,464	5,991	5,910
Interest expense	(25)	0	0
Non-cash operating lease cost	1,531	1,179	0
Goodwill impairment charge	42,520	0	0
Change in fair value of contingent consideration	(28,666)	0	0
Loss on disposal of fixed assets	265	927	152
Loss on impairment of intangible asset	2,439	389	0
Stock-based compensation expense	5,386	6,087	11,046
Deferred income taxes	(3,543)	794	(1,817)
Provision (recovery) for doubtful accounts	549	(499)	57
Provision for inventory	5,490	1,612	4,419
Amortization of acquisition related inventory step-up	11,082	0	0
Amortization of premium and accretion of discount on investments and cash equivalents	13	(25)	(371)
Changes in operating assets and liabilities:
Accounts receivable	5,855	(1,839)	2,914
Inventories	(14,177)	(5,585)	(7,577)
Prepaid expenses, other current and long-term assets	(1,783)	(1,641)	899
Accounts payable	822	767	(1,671)
Operating lease liabilities	(1,439)	(1,065)	0
Accrued expenses, other current and long-term liabilities	(142)	3,805	1,313
Income taxes	(2,072)	(1,085)	922
Contingent consideration	(522)	0	0
Net cash provided by operating activities	13,065	37,005	34,918
Cash flows from investing activities:
Acquisition of Parcus Medical and Arthrosurface, net of cash acquired	(94,601)	0	0
Proceeds from maturities of investments	45,000	146,366	46,000
Purchases of investments	(20,035)	(103,848)	(91,601)
Purchases of property and equipment	(1,628)	(2,827)	(4,656)
Net cash provided by (used in) investing activities	(71,264)	39,691	(50,257)
Cash flows from financing activities:
Payments made on finance leases	(208)	0	0
Proceeds from long term debt	50,000	0	0
Repayments of long term debt	(50,350)	0	0
Repurchases of common stock	0	(30,000)	(30,000)
Cash paid for tax withheld on vested restricted stock awards	(262)	(293)	(1,790)
Proceeds from exercises of equity awards	1,524	22,151	2,886
Contingent consideration paid	(4,478)	0	0
Net cash provided by (used in) provided by financing activities	(3,774)	(8,142)	(28,904)
Exchange rate impact on cash	327	(133)	29
Increase (decrease) in cash and cash equivalents	(61,646)	68,421	(44,214)
Cash and cash equivalents at beginning of period	157,463	89,042	133,256
Cash and cash equivalents at end of period	95,817	157,463	89,042
Supplemental disclosure of cash flow information:
Cash paid for income taxes	993	9,257	5,560
Right-of-use assets obtained in exchange for operating lease liabilities as of January 1, 2019	2,340	1,980
Non-cash investing activities:
Purchases of property and equipment included in accounts payable and accrued expenses	17	137	351
Consideration for acquisitions included in accounts payable and accrued expenses	476	0	0
Contingent consideration fair value on acquisition date	69,076	0	0
Accounting Standards Update 2016-02 [Member]
Supplemental disclosure of cash flow information:
Right-of-use assets obtained in exchange for operating lease liabilities as of January 1, 2019	$ 0	$ 24,110	$ 0