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:
Income from continuing operations	$ 60,537	$ (92,295)	$ 15,110
Loss from discontinued operations	(689)	(505)	(452)
Net income (loss)	59,848	(92,800)	14,658
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	9,448	10,811	8,942
Bad debt expense	332	19	27
Inventory lower-of-cost-or-market/NRV adjustments	2,391	770	558
Stock-based compensation expense	3,734	619	1,981
Loss on asset disposals	709	1,191	32
Loss on debt extinguishment	230	0	0
Loss on disposal group, goodwill and other intangible impairment charge	20,668	72,008	0
Deferred income taxes, net of valuation allowances	(2,008)	(10,613)	3,229
Other	(832)	(90)	133
Changes in operating assets and liabilities:
Trade receivables	(41,565)	(8,790)	(3,030)
Inventories	(9,584)	13,237	(15,634)
Prepaids and other current assets	(6,682)	3,012	(495)
Income taxes receivable	(3,550)	5,181	(5,636)
Trade payables	21,819	(13,451)	19,312
Accrued liabilities, including warranty obligations	14,202	(3,677)	(2,826)
Net cash provided by (used in) operating activities	71,660	(22,573)	21,251
Cash flows from investing activities:
Acquisition of business, net of cash acquired	0	0	(2,750)
Proceeds from the sale of disposal group	21,410	0	0
Purchases of property, plant and equipment and intangible assets	(9,727)	(8,952)	(10,380)
Purchases of available-for-sale-securities	(36,199)	0	(29,522)
Proceeds from maturities of available-for-sale securities	0	25,271	61,365
Impairment Of Other Investments In Non Controlled Affiliates	2,500	0	0
Purchases of other investments in non-controlled affiliates	0	(3,500)	0
Net cash (used in) provided by investing activities	(24,516)	12,819	18,713
Cash flows from financing activities:
Proceeds from long-term debt	45,758	32,968	0
Payments on long-term debt	45,101	50,667	16,000
Debt issuance costs	(1,842)	0	0
Proceeds from employee stock purchases	256	241	444
Tax payments related to stock award issuances	51	75	366
Excess tax benefit related to stock-based awards	(2,240)	(107)	(396)
Payments for stock repurchases	0	0	(12,996)
Net cash used in financing activities	(3,118)	(17,490)	(28,582)
Effect of exchange rate changes on cash and cash equivalents	2,824	189	(1,150)
Increase (decrease) in cash, cash equivalents and restricted cash	46,850	(27,055)	10,232
Cash and cash equivalents at beginning of period	11,070	38,125	27,893
Cash, cash equivalents and restricted cash at end of period	57,920	11,070	38,125
Supplemental disclosure of cash flow information:
Cash paid (received) for income taxes, net	17,300	(4,186)	8,885
Cash paid for interest	889	1,197	1,044
Capital expenditures incurred but not yet paid	908	420	1,220
Cash and cash equivalents at beginning of period	11,070	38,125
Total cash, cash equivalents and restricted cash	$ 57,920	$ 38,125	$ 27,893