CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating activities
Net loss	$ (4,386)	$ (4,732)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Provision for doubtful accounts	4,434	5,870
Depreciation	4,551	3,761
Stock-based compensation	1,711	1,830
Amortization of intangibles	1,193	371
Deferred income tax assets (liabilities)		(550)
Amortization of investment premium		229
Decrease in deferred rent	(172)	(163)
Changes in operating assets and liabilities:
Accounts receivable	(3,163)	(7,600)
Inventory	(789)	114
Prepaid expenses and other assets	(1,724)	(264)
Accounts payable	1,586	(542)
Accrued and other liabilities	921	(2,188)
Net cash provided by (used in) operating activities	4,162	(3,864)
Investing activities
Acquisition of business, net of cash acquired		(5,768)
Purchases of property and equipment	(3,425)	(2,748)
Purchases of short-term available-for-sale investments		(10,536)
Sale or maturity of short-term available-for-sale investments		17,335
Net cash used in investing activities	(3,425)	(1,717)
Financing activities
Proceeds from the exercise of employee stock options and employee stock purchase plan contributions	271	241
Net cash provided by financing activities	271	241
Net increase (decrease) in cash and cash equivalents	1,008	(5,340)
Cash and cash equivalents - beginning of period	18,298	18,531
Cash and cash equivalents - end of period	19,306	13,191
Supplemental disclosure of cash flow information
Cash paid for taxes	$ 105	$ 83