CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 26,143	$ 19,311	$ 7,370
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	9,158	7,849	8,896
Loss on disposal of fixed assets	17	35	145
Share–based compensation expense	5,468	5,651	5,832
Deferred income tax benefit	(728)	(248)	(1,560)
Other non-cash charges	67	22	48
Changes in operating assets and liabilities:
Receivables	(6,179)	(4,468)	749
Inventories	(3,631)	(811)	(2,451)
Other assets	(2,972)	(932)	1,192
Accounts payable	4,336	4,688	6,018
Accrued payroll and related benefits	1,006	(173)	5,397
Deferred revenue	1,194	196	885
Income taxes	(1,873)	3,051	2,316
Other accrued expenses and liabilities	(834)	(1,364)	549
Net cash provided by operating activities	31,172	32,807	35,386
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of short term investments	(16,811)	(8,225)	(24,513)
Proceeds from sales of short term investments	24,030	8,121	11,137
Capital additions	(12,986)	(8,265)	(7,614)
Proceeds from the sale of fixed assets	0	0	28
Cash paid for acquisition of a business	(15,000)	0	0
Net cash used in investing activities	(20,767)	(8,369)	(20,962)
CASH FLOWS FROM FINANCING ACTIVITIES:
Exercise of stock options	3,182	314	0
Taxes related to equity compensation awards, net	512	(1,534)	(825)
Payment of dividends	(20,504)	(20,370)	(20,013)
Debt issuance costs	(24)	0	0
Net cash used in financing activities	(16,834)	(21,590)	(20,838)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(6,429)	2,848	(6,414)
CASH AND CASH EQUIVALENTS, beginning of year	12,620	9,772	16,186
CASH AND CASH EQUIVALENTS, end of year	$ 6,191	$ 12,620	$ 9,772