Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 29, 2014	Mar. 30, 2013
Operating activities
Net loss	$ (4,521)	$ (8,264)
Adjustments to reconcile net loss to net cash and cash equivalents provided by (used in) operating activities:
Depreciation and amortization	1,190	1,032
Net amortization of investment premiums and discounts	208	228
Equity-based compensation	697	563
Change in the fair value of acquisition-related contingent consideration	51	111
Deferred income taxes	(163)	(768)
Loss on divestiture		208
Changes in operating assets and liabilities	(1,909)	7,267
Total adjustments	74	8,641
Net cash and cash equivalents provided by (used in) operating activities	(4,447)	377
Investing activities
Purchases of investments	(2,996)	(15,783)
Proceeds from sales and maturities of investments	16,230	14,664
Proceeds from sale of DeltaNu assets		500
Purchases of leasehold improvements and equipment	(1,401)	(301)
Net cash and cash equivalents provided by (used in) investing activities	11,833	(920)
Financing activities
Proceeds from issuance of common stock	1,000	1,130
Common stock repurchases	(1,140)
Net cash and cash equivalents provided by (used in) financing activities	(140)	1,130
Effect of exchange rate changes on cash and cash equivalents	(30)	(6)
Net increase in cash and cash equivalents	7,216	581
Cash and cash equivalents at beginning of period	20,121	24,261
Cash and cash equivalents at end of period	$ 27,337	$ 24,842