Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net (loss) income	$ (1,123)	$ 1,963
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Provision for doubtful accounts	47	72
Depreciation and amortization	1,693	1,224
Deferred income taxes	(289)	683
Loss on derivative instruments	21	31
Compensation expense related to stock-based awards and employee stock purchase plan	1,003	1,082
Changes in operating assets and liabilities:
Accounts receivable	(698)	(1,825)
Inventories	(459)	(721)
Prepaid expenses and other assets	(984)	(813)
Other non-current assets	245	227
Accounts payable	(421)	(332)
Deferred revenue	907	182
Accrued expenses	(503)	(565)
Other long-term liabilities	(10)	1,170
Net cash (used in) provided by operating activities	(571)	2,378
Cash flows from investing activities:
Capital expenditures	(771)	(790)
Purchases of marketable securities	(9,287)	(12,705)
Maturities and sales of marketable securities	14,256	3,701
Net cash provided by (used in) investing activities	4,198	(9,794)
Cash flows from financing activities:
Repayments of long-term debt	(314)	(116)
Borrowings from long-term debt	0	4,671
Proceeds from stock options exercised and employee stock purchase plan	129	1,199
Payment of employee restricted stock withholdings	(481)	(828)
Net cash (used in) provided by financing activities	(666)	4,926
Effect of exchange rate changes on cash and cash equivalents	(36)	41
Net increase (decrease) in cash and cash equivalents	2,925	(2,449)
Cash and cash equivalents at beginning of period	9,358	8,978
Cash and cash equivalents at end of period	$ 12,283	$ 6,529