Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Operating Activities:
Net loss	$ (16,069)	$ (17,340)	$ (15,082)	$ (16,598)		$ (46,581)	$ (45,521)
Adjustments to reconcile net loss to net cash and cash equivalents used in operating activities:
Depreciation						2,416	2,015
Amortization of intangible assets	2,804		2,780			8,533	7,964
Amortization of discounts and premiums on investments, net						65	0
Stock-based compensation						6,589	5,800
Gain on extinguishment of debt	0		0			(2,847)	0
Deferred tax benefit						(4)	(1,386)
Write down of inventory	100		0			377	0
Change in fair value of warrant liabilities	(0)		(63)		$ 2,000	1,981	206
Change in fair value of contingent consideration	278		502			1,013	1,770
Changes in operating assets and liabilities:
Accounts receivable						113	(252)
Inventories						(1,941)	(4,410)
Operating lease right-of-use assets						(3,174)	(1,045)
Prepaid expenses						1,220	1,269
Employee retention tax credit receivable						(1,311)	0
Other current and long-term assets						2,098	2,009
Accounts payable						1,376	(706)
Accrued expenses						(588)	(1,772)
Deferred revenue						(81)	(56)
Operating lease liabilities						3,259	1,115
Other long-term liabilities						0	(910)
Net cash and cash equivalents used in operating activities						(27,487)	(33,910)
Investing Activities:
Purchase of available-for-sale investments						(88,232)	0
Purchase of property and equipment						(838)	(3)
Net cash and cash equivalents used in investing activities						(89,070)	(3)
Financing Activities:
Proceeds from issuance of common stock, preferred stock and warrants under 2020 financing, net of issuance costs						0	13,525
Proceeds from issuance of common stock, net of issuance costs						130,361	24,861
Proceeds from notes payable, net of issuance costs						0	2,815
Taxes paid related to net share settlement of vesting of restricted stock units						(1,058)	(33)
Payment of contingent consideration						0	(74)
Proceeds from exercise of stock options and warrants						30,838	3,340
Net cash and cash equivalents provided by financing activities						160,141	44,434
Effect of exchange rate changes on cash and cash equivalents						(181)	30
Net increase in cash, cash equivalents and restricted cash						43,403	10,551
Cash, cash equivalents and restricted cash, beginning of period		$ 17,529		$ 10,567	$ 17,529	17,529	10,567	$ 10,567
Cash, cash equivalents and restricted cash, end of period	$ 60,932		$ 21,118			60,932	21,118	$ 17,529
Supplemental Schedule of Non-cash Investing and Financing Activities:
Transfer of inventories to property and equipment						2,156	5,839
Reclass of warrant liability to common stock and additional paid-in-capital						2,236	0
Lease liabilities arising from obtaining right-of-use assets						3,857	0
Exchange of common stock for Series B Warrants						0	2,470
Transfer of in-process research and development to intellectual property						0	2,425
Conversion of preferred stock to common stock						$ 0	$ 79