CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Operating activities    
Net loss $ (4,231) $ (539)
Adjustments to reconcile net loss to net cash used in operating activities:    
Depreciation expense 603 608
Amortization of intangible assets 325 98
Provision for doubtful accounts 71 59
Stock-based compensation 1,849 1,247
Changes in assets and liabilities:    
Accounts receivable 1,716 (603)
Inventories (3,389) (1,783)
Prepaid expenses and other current assets (375) (246)
Other assets 47 (23)
Accounts payable 519 1,038
Accrued liabilities (1,049) (1,408)
Deferred revenue 86 122
Other long-term liabilities (347) (17)
Net cash used in operating activities (4,175) (1,447)
Investing activities    
Purchases of available-for-sale investments (25,500) (59,775)
Proceeds from sales of available-for-sale investments   1,043
Proceeds from maturities of available-for-sale investments 24,095  
Purchases of property and equipment (808) (389)
Business acquisitions, net of cash acquired (8,380)  
Net cash used in investing activities (10,593) (59,121)
Financing activities    
Proceeds from exercise of options for common stock 491 3,199
Repayment of notes payable (267) (297)
Net cash provided by financing activities 224 2,902
Effect of exchange rate changes on cash and cash equivalents (6) 5
Net decrease in cash and cash equivalents (14,550) (57,661)
Cash and cash equivalents at beginning of period 29,187 84,546
Cash and cash equivalents at end of period 14,637 26,885
Supplemental disclosure of cash flow information    
Cash paid for interest 36 39
Cash paid for taxes 66 93
Supplemental schedule of non-cash investing and financing activities    
Landlord paid tenant improvements 53  
Net unrealized gains (losses) on available-for-sale investments $ 40 $ (33)