Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities:
Net loss	$ (922)	$ (1,344)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Provision for doubtful accounts	145	113
Depreciation and amortization	2,206	2,209
Deferred income taxes	464	(175)
Loss on interest rate swaps	64	36
Compensation expense related to stock-based awards and employee stock purchase plan	1,868	1,826
Changes in operating assets and liabilities:
Accounts receivable	3,493	(1,693)
Inventories	1,454	(2,519)
Prepaid expenses and other assets	(401)	30
Other non-current assets	(370)	(598)
Accounts payable	(333)	1,263
Deferred revenue	(22)	(150)
Accrued expenses	(863)	51
Other long-term liabilities	(7)	115
Net cash provided by (used in) operating activities	6,776	(836)
Cash flows from investing activities:
Capital expenditures	(4,536)	(3,964)
Purchases of marketable securities	(8,705)	(21,557)
Maturities and sales of marketable securities	9,473	27,005
Net cash (used in) provided by investing activities	(3,768)	1,484
Cash flows from financing activities:
Repayments of long-term debt	(65)	(61)
Proceeds from stock options exercised and employee stock purchase plan	695	791
Payment of employee restricted stock withholdings	(333)	(625)
Repayments of line of credit borrowings	(2,000)
Payment of stock registration fee		(10)
Net cash (used in) provided by financing activities	(1,703)	95
Effect of exchange rate changes on cash and cash equivalents	(80)	(60)
Net increase in cash and cash equivalents	1,225	683
Cash and cash equivalents at beginning of period	7,017	7,241
Cash and cash equivalents at end of period	$ 8,242	$ 7,924