Consolidated Statements of Cash Flows (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Operating activities      
Net gain (loss) $ 1,012 [1] $ (107,406) [2] $ (117,029)
Adjustments to reconcile net earnings (loss) to net cash used in operating activities:      
Revenue Recognition, Multiple-deliverable Arrangements, Determination of Selling Price, Amount (21,000) 0 0
Gain on sale of discontinued operations 24,291 0 0
(Earnings) loss from discontinued operations, net of tax 583 (2,161) (262)
Depreciation and amortization 12,232 14,174 10,469
Share-based compensation 11,519 9,527 10,790
Noncash restructuring costs 1,907 2,358 0
Other non cash items 387 1,111 2,241
Changes in operating assets and liabilities:      
Accounts receivable (6,579) (1,747) (805)
Inventories 5,082 (6,636) (1,925)
Prepaid expenses and other assets (1,675) (151) 1,292
Accounts payable and accrued expenses (5,681) 2,099 12,399
Other liabilities (1,582) 737 29
Net cash used in operating activities (28,086) (88,095) (82,801)
Investing activities:      
Purchases of property, equipment and leasehold improvements (2,236) (12,071) (12,918)
Purchases of marketable securities (45,128) (52,826) (57,739)
Maturities of marketable securities 24,203 95,393 60,928
Payment for the purchase of intangible assets (9,250) 0 0
Net cash received from sale of segment 29,291 0 0
Proceeds from pooled patents agreement 42,150 0 0
Distribution from pooled patents agreement (6,150) 0 0
Net cash paid for other assets 0 (483) (1,891)
Net cash provided by (used in) investing activities 32,880 30,013 (11,620)
Financing activities:      
Payments on long-term obligations (7,541) (7,574) (2,631)
Borrowings on term loan and capital lease obligations 0 0 5,390
Proceeds from issuance of convertible debt, net of issuance costs 0 0 124,728
Proceeds from stock offering, net of issuance costs 0 0 58,161
Proceeds from common stock issued under employee stock plans 1,833 1,473 1,123
Repurchase of common stock in satisfaction of tax withholding obligations in connection with the vesting of restricted stock units (708)    
Net cash provided by (used in) financing activities (5,708) (6,101) 186,771
Discontinued operations:      
Net cash provided by operating activities of discontinued operations 2,816 2,456 4,785
Net cash used in investing activities of discontinued operations (164) (643) (2,310)
Net cash provided by discontinued operations 2,652 1,813 2,475
Effect of exchange rate changes on cash and cash equivalents (18) 157 51
Net increase (decrease) in cash and cash equivalents 1,720 (62,213) 94,876
Cash and cash equivalents at beginning of year 61,589 123,802 28,926
Cash and cash equivalents at end of year 63,309 61,589 123,802
Supplemental disclosure of cash flow information:      
Cash paid for interest 7,129 7,386 724
Supplemental non-cash items:      
Plant and equipment acquired with financing and capital lease obligations $ 0 $ 0 $ 2,250
[1] Net earnings during the fourth quarter of 2014 includes a $22.9 million gain from the Pooled Patents Agreement. That gain was offset by a $1.2 million tax expense due to a reduction in a tax benefit estimated in the prior quarter. The first and second quarter of 2014 include restructuring costs of $0.9 million and $1.0 million, respectively.
[2] Net loss during the third quarter of 2013 includes $5.7 million in restructuring costs and impairment charges.