CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net (loss) income	$ 2,557	$ (6,978)	$ 2,143	$ (2,424)	$ (11,245)	$ 1,710
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation					18,705	15,200
Loss on disposal of assets					371	451
Loss on extinguishment of debt	0		0		1,400	1,018	$ 1,400
Loss on termination of cash flow hedge	0		0		3,506	0
Amortization of intangibles	2,500		2,400		7,387	7,482
Amortization of debt issue costs					138	323
Amortization of convertible debt discount					2,705	0
Non-cash stock-based compensation					7,536	7,727
Non-cash operating lease expense					6,365	3,224
Changes in assets and liabilities, net
Accounts receivable, net					(9,455)	(14,219)
Inventories					(5,704)	(3,982)
Prepaid and other assets					(4,189)	(1,013)
Prepaid lease asset					(10,142)	0
Other current assets					(2,568)	(381)
Accounts payable, accrued and other liabilities					(9,335)	2,470
Net cash (used in) provided by operating activities					(4,525)	20,010
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of marketable securities					(53,396)	0
Proceeds from sale of marketable securities					3,000	0
Purchases of property and equipment					(17,591)	(13,953)
Business acquisition					(37,000)	0
Investment in non-consolidated affiliate					(25,600)	0
Acquisition working capital adjustment					0	399
Net cash used in investing activities					(130,587)	(13,554)
CASH FLOWS FROM FINANCING ACTIVITIES
Repayment of revolving credit facility					0	(5,000)
Repayment of equipment financing obligations					(4,331)	(5,481)
Proceeds from term loan					0	100,000
Repayment of term loan					(97,540)	(96,750)
Cash flow hedge termination					(3,317)	0
Payments of debt issuance costs					0	(1,051)
Issuance of common stock, net					10,761	10,132
Proceeds from issuance of convertible debt, net of issuance costs					194,466	0
Proceeds from equity offering, net of issuance costs					127,293	160,774
Net cash provided by financing activities					227,332	162,624
Net change in cash, cash equivalents and restricted cash					92,220	169,080
Cash, cash equivalents and restricted cash, beginning of period		$ 173,016		$ 9,811	173,016	9,811	9,811
Cash, cash equivalents and restricted cash, end of period	265,236		178,891		265,236	178,891	173,016
Cash and cash equivalents	233,233		178,891		233,233	178,891	173,016
Restricted cash, non-current	$ 32,003		$ 0		32,003	0	$ 0
Supplemental disclosure of cash flow information:
Interest paid					1,638	4,295
Income taxes paid, net					209	316
Supplemental disclosure of non-cash investing and financing information:
Working capital adjustment related to acquisition					0	1,977
Equipment acquired under financing obligations					428	3,665
Property and equipment included in accounts payable					$ 3,521	$ 810