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 loss	$ (49,284)	$ (25,580)	$ (29,979)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Effect of change in revenue recognition	0	(17,382)	0
Share-based compensation	15,357	12,064	14,768
Loss on extinguishment of debt	8,201	0	0
Depreciation	5,782	6,546	5,882
Amortization of deferred financing costs and debt discount	2,276	1,431	137
Amortization of intangible assets	1,073	1,039	1,034
Impairment of intangible assets	1,027	1,258	0
Non cash lease expenses	983	947	0
Accretion of asset retirement obligation	10	0	0
Loss on fixed asset disposal	1	318	0
Amortization of discount on notes receivable	0	0	(190)
Change in deferred income taxes	0	0	25,541
Increase (decrease) in cash resulting from changes in:
Accounts receivable	(3,096)	(10,938)	0
Inventory	(1,257)	6,882	(6,519)
Prepaid expenses	1,064	4	(4,548)
Other assets	(119)	(5,770)	3,562
Accounts payable	177	(6,171)	6,585
Accrued compensation	(2,459)	(1,722)	2,083
Accrued expenses	1,746	(57)	16,074
Income taxes	(10,027)	436	202
Other liabilities	(1,718)	(2,717)	1,164
Net cash flows (used in) provided by operating activities	(30,263)	(39,412)	35,796
Cash flows from investing activities:
Purchases of property and equipment	(4,228)	(1,752)	(9,419)
Patent application costs	(327)	(466)	(609)
Principal payments from note receivable	0	2,722	778
Proceeds from property and equipment sale	0	0	30
Net cash flows (used in) provided by investing activities	(4,555)	504	(9,220)
Cash flows from financing activities:
Proceeds from sale of Series B convertible preferred stock	100,000	0	0
Stock issuance costs	(7,470)	0	0
Proceeds from term loans	59,500	72,750	0
Deferred financing costs	(3,235)	(6,650)	0
Repayment of term loans	(83,872)	(1,875)	0
Prepayment premium on early repayment of term loan	(1,439)	0	0
Stock repurchased for tax withholdings on vesting of restricted stock	(2,334)	(1,474)	(4,914)
Proceeds from exercise of stock options	411	108	3,555
Stock repurchase under repurchase plan	0	0	(7,572)
Payments under capital lease obligations	0	0	(3)
Net cash flows provided by (used in) financing activities	61,561	62,859	(8,934)
Net change in cash	26,743	23,951	17,642
Cash and cash equivalents, beginning of year	69,069	45,118	27,476
Cash and cash equivalents, end of year	$ 95,812	$ 69,069	$ 45,118