CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating activities
Net loss	$ (2,087)	$ (3,534)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Provision for doubtful accounts	2,467	2,911
Provision for excess inventory		55
Depreciation	2,389	1,846
Stock-based compensation	700	855
Amortization of intangibles	619	174
Amortization of investment premium		122
Decrease in deferred rent	(110)	(80)
Changes in operating assets and liabilities:
Accounts receivable	(2,375)	(2,422)
Inventory	(224)	497
Prepaid expenses and other assets	(48)	(102)
Accounts payable	885	(657)
Accrued and other liabilities	(559)	(1,614)
Net cash provided by (used in) operating activities	1,657	(1,949)
Investing activities
Acquisition of business, net of cash acquired		(6,338)
Purchases of property and equipment	(1,839)	(1,372)
Purchases of short-term available-for-sale investments		(9,637)
Sale or maturity of short-term available-for-sale investments		13,847
Net cash used in investing activities	(1,839)	(3,500)
Financing activities
Proceeds from the exercise of employee stock options and employee stock purchase plan contributions	208	240
Net cash provided by financing activities	208	240
Net increase (decrease) in cash and cash equivalents	26	(5,209)
Cash and cash equivalents - beginning of period	18,298	18,531
Cash and cash equivalents - end of period	18,324	13,322
Supplemental disclosure of cash flow information
Cash paid for taxes	$ 100	$ 20