Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net loss	$ (33,168)	$ (24,644)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	13,745	10,577
Depreciation	3,815	3,925
Amortization of intangible assets	965	977
Amortization of deferred financing costs	249	282
Loss on disposal of property and equipment	52	97
Amortization of investments	1,206	127
Change in value of contingent consideration	5,100	(5,046)
Other non-cash adjustments to income	472	656
Changes in operating assets and liabilities
Accounts receivable	(10,799)	5,127
Inventories	(2,707)	(3,402)
Other current assets	(308)	(7)
Accounts payable	3,571	(1,970)
Accrued liabilities	4,529	(14,841)
Other noncurrent assets and liabilities	(571)	507
Net cash used in operating activities	(13,849)	(27,635)
Cash flows from investing activities:
Purchases of available-for-sale securities	(94,817)	(127,069)
Sales and maturities of available-for-sale securities	147,884	33,732
Purchases of property and equipment	(5,539)	(2,944)
Proceeds from capital grant		800
Net cash provided by (used in) investing activities	47,528	(95,481)
Cash flows from financing activities:
Proceeds from sale of stock, net of offering costs of $0 and $218		188,958
Payments on debt and leases	(399)	(280)
Payments of debt fees		(4)
Proceeds from stock option exercises and employee stock purchase plan	9,010	6,889
Shares repurchased for payment of taxes on stock awards	(16,500)	(12,323)
Net cash (used in) provided by financing activities	(7,889)	183,240
Effect of exchange rate changes on cash and cash equivalents	(115)	(85)
Net increase in cash and cash equivalents	25,675	60,039
Cash and cash equivalents-beginning of period	41,944	28,483
Cash and cash equivalents-end of period	67,619	88,522
Supplemental cash flow information:
Cash paid for interest	2,147	2,195
Cash paid for income taxes, net of refunds	128	282
Non-cash investing and financing activities:
Accrued purchases of property and equipment	$ 529	$ 525