CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities
Net loss	$ (41,240)	$ (34,318)
Adjustments to reconcile net loss to net cash used in operating activities
Stock-based compensation expense	7,197	4,580
Depreciation and amortization	4,181	3,371
Provision for bad debts	(110)	251
Provision for inventory valuation	(285)	(428)
Non-cash lease expense	1,304	797
Change in fair value of contingent consideration	(457)
Loss on disposal of property and equipment	126	13
Amortization of discount on debt	55	190
Deferred income taxes	12
Changes in operating assets and liabilities, net of acquisition:
Accounts receivable	2,776	(2,916)
Inventories	(4,576)	(15,468)
Prepaid expenses and other assets	(1,102)	(1,039)
Accounts payable	(854)	2,803
Contract liabilities	(658)	332
Accrued expenses and other current liabilities	(4,286)	10,520
Operating lease liabilities, current and long-term	(1,305)	(797)
Net cash used in operating activities	(39,222)	(32,109)
Cash flows from investing activities
Purchases of property and equipment	(4,814)	(5,944)
Net cash used in investing activities	(4,814)	(5,944)
Cash flows from financing activities
Proceeds from short-term line of credit		995
Payments on short-term line of credit	(3,163)
Proceeds from exercise of stock options	1,405	485
Proceeds from issuance of common stock in connection with public offering		94,155
Common stock offering costs		(471)
Net cash provided by (used in) financing activities	(907)	105,451
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(5)	(37)
Net increase (decrease) in cash, cash equivalents and restricted cash	(44,948)	67,361
Cash, cash equivalents and restricted cash
Beginning of period	115,536	73,507
End of period	70,588	140,868
Supplemental disclosures of cash flow information
Interest paid during the period	1,862	3,670
Property and equipment purchases in accounts payable and accrued expenses	133	139
Issuance of common stock upon vesting of restricted stock units	133	162
At-The-Market offering
Cash flows from financing activities
Proceeds from issuance of common stock in connection with public offering		9,927
Employee Stock Purchase Plan
Cash flows from financing activities
Proceeds from issuance of common stock under Employee Stock Purchase Plan	$ 851	$ 360