CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash provided by operating activities:
Net income	$ 20,384	$ 29,173	$ 32,534
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	26,967	20,452	18,244
Provision for doubtful accounts	183	299	249
Provision for inventory write-downs	3,806	3,382	3,473
Deferred income taxes	(1,637)	(5,348)	(538)
Tax benefit from exercise of stock options and vested restricted stock	2,007	3,069	0
Excess tax benefit from stock-based compensation	(1,970)	(2,619)	0
Shares issued for employee benefit plan	913	868	847
Employee and director stock-based compensation	10,324	7,913	6,444
Performance-based common stock warrants	2,728	0	0
Changes in operating assets and liabilities:
Restricted cash	0	(4,623)	0
Accounts receivable	(3,882)	(29,407)	(7,966)
Inventories	(14,800)	(31,877)	(8,161)
Prepaid expenses and other assets	(772)	774	(2,803)
Accounts payable and accrued expenses	10,451	33,309	19,964
Accrued income taxes	(5,159)	729	1,186
Net cash provided by operating activities	49,543	26,094	63,473
Cash used for investing activities:
Acquisition of property, plant, and equipment	(40,651)	(32,989)	(16,566)
Acquisition of intangible assets	(1,912)	(2,395)	(1,853)
Increase in restricted cash	(4,797)	0	0
Deposit received toward sale of Guangzhou factory	4,797	0	0
Deconsolidation of Encore Controls LLC	48	0	0
Acquisition of net assets of Ecolink Intelligent Technology, Inc., net of cash acquired	0	(12,265)	0
Net cash used for investing activities	(42,515)	(47,649)	(18,419)
Cash provided by (used for) financing activities:
Borrowings under line of credit	147,974	84,500	0
Repayments on line of credit	(147,987)	(34,500)	0
Proceeds from stock options exercised	6,244	1,712	8,122
Treasury stock purchased	(12,647)	(89,395)	(16,168)
Distribution to noncontrolling interest	0	(78)	0
Excess tax benefit from stock-based compensation	1,970	2,619	0
Net cash provided by (used for) financing activities	(4,446)	(35,142)	(8,046)
Effect of exchange rate changes on cash	(4,937)	(2,858)	(661)
Net increase (decrease) in cash and cash equivalents	(2,355)	(59,555)	36,347
Cash and cash equivalents at beginning of year	52,966	112,521	76,174
Cash and cash equivalents at end of period	50,611	52,966	112,521
Supplemental cash flow information:
Income taxes paid	9,891	7,793	7,178
Interest paid	$ 1,208	$ 255	$ 0