Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales		$ 155,391	$ 61,708	$ 363,301	$ 205,112
Cost of sales		87,453	42,641	212,370	132,686
Gross profit		67,938	19,067	150,931	72,426
Operating expenses:
Selling and marketing		19,207	17,472	56,339	69,146
General and administrative		8,841	6,726	25,812	23,824
Research and development		4,240	3,122	11,783	11,282
Loss on disposal		(8,345)	0	20,668	72,008
Total operating expenses		23,943	27,320	114,602	176,260
Operating income (loss)		43,995	(8,253)	36,329	(103,834)
Other expense:
Interest income		1	0	4	162
Interest expense		(253)	(293)	(1,218)	(721)
Other, net		(376)	(129)	(220)	(351)
Total other expense, net		(628)	(422)	(1,434)	(910)
Income (loss) from continuing operations before income taxes		43,367	(8,675)	34,895	(104,744)
Income tax expense (benefit)	[1]	9,398	55	3,610	(8,786)
Income (loss) from continuing operations		33,969	(8,730)	31,285	(95,958)
Discontinued operations:
Loss from discontinued operations before income taxes		(34)	(39)	(97)	(104)
Income tax expense of discontinued operations		97	75	276	225
Loss from discontinued operations		(131)	(114)	(373)	(329)
Net income (loss)		$ 33,838	$ (8,844)	$ 30,912	$ (96,287)
Earnings Per Share, Basic [Abstract]
Basic income (loss) per share from continuing operations (in dollars per share)		$ 1.13	$ (0.29)	$ 1.05	$ (3.24)
Basic loss per share from discontinued operation (in dollars per share)		0	(0.01)	(0.02)	(0.01)
Basic net income (loss) per share (in dollars per share)		1.13	(0.30)	1.03	(3.25)
Earnings Per Share, Diluted [Abstract]
Diluted income (loss) per share from continuing operations (in dollars per share)		1.05	(0.29)	0.98	(3.24)
Diluted loss per share from discontinued operation (in dollars per share)		(0.01)	(0.01)	(0.01)	(0.01)
Diluted net income (loss) per share (in dollars per share)		$ 1.04	$ (0.30)	$ 0.97	$ (3.25)
Shares used in per share calculations:
Basic (in shares)		30,038	29,728	29,914	29,660
Diluted (in shares)		32,401	29,728	31,792	29,660

[1] (1) Income tax expense (benefit) for the quarter and nine months ended September 30, 2019 includes an immaterial correction to reduce income tax expense and the valuation allowance by $1.8 million. The correction reflects the impact of 2017 tax reform associated with the application of indefinite-lived deferred taxes to properly calculate the valuation allowance.