Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 9,641	$ 4,431
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	1,609	1,513
Amortization of stock based compensation	1,066	762
Loss on disposal of property and equipment	13	19
Deferred restricted stock unit compensation	(647)	0
Provision for inventory valuation	88	(111)
Deferred tax assets	(3,702)	0
Changes in assets and liabilities:
Accounts receivable	(1,416)	594
Inventories	(258)	787
Prepaid expenses and other current assets	(452)	19
Other assets	(87)	8
Accounts payable	2,944	(1,285)
Accrued expenses	491	(1,009)
Other long-term liabilities	53	17
Net cash provided by operating activities	9,343	5,745
Cash flows from investing activities:
Purchase of short-term investments	(32,140)	(14,893)
Proceeds from sales and maturities of short-term investments	29,427	26,425
Purchase of long-term investments	(176)	(10,098)
Purchase of property and equipment	(1,450)	(1,635)
Net cash used in investing activities	(4,339)	(201)
Cash flows from financing activities:
Proceeds from issuance of common stock under ESPP	416	414
Proceeds from the exercise of common stock options	888	399
Repurchase of common stock	(4,780)	(325)
Payment of dividends	(10,960)	0
Repayment of bank borrowings	(230)	(95)
Net cash (used in) provided by financing activities	(14,666)	393
Effect of exchange rate changes on cash and cash equivalents	635	(157)
Net (decrease) increase in cash and cash equivalents	(9,027)	5,780
Cash and cash equivalents at beginning of year	13,820	8,040
Cash and cash equivalents at end of year	4,793	13,820
Supplemental disclosure of cash flow information:
Cash paid for interest	(4)	(9)
Cash paid for income taxes	$ (450)	$ (98)