| In millions, except per share items | Jun-30-14 | Mar-31-14 | Dec-31-13 | Sep-30-13 | Jun-30-13 | Mar-31-13 | Dec-31-12 | Sep-30-12 |
| | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K | 10-Q |
| Cash flows from operating activities: | | | | | | | | |
| Net income | 11.4 | 13.8 | 14.3 | -19.3 | -31.9 | -54.5 | -64.6 | -37.4 |
| Adjustments to reconcile net income to net cash flows from operating activities, net of assets acquired and liabilities assumed: | | | | | | | | |
| Depreciation and amortization | 1.5 | 1.6 | | | 1.7 | 0.6 | | |
| Share-based compensation expense | 3.8 | 3.9 | 4.1 | 3.2 | 2.7 | 2.5 | | 2.5 |
| Write-downs of inventories | 0.9 | 0.9 | 0.9 | 0.7 | 0.7 | 0.6 | | 1.4 |
| Other non-cash items | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | | 0.1 |
| Changes in operating assets and liabilities: | | | | | | | | |
| Accounts receivable | -3.3 | -4.7 | -6.1 | -5.3 | -2.5 | -2.6 | | -1.3 |
| Inventories | -1.9 | -0.2 | 0.2 | -3.3 | -4.5 | -7.0 | -7.3 | 0.2 |
| Other current assets | -1.1 | -2.0 | -2.1 | -1.9 | -0.6 | 0.7 | | 1.0 |
| Other assets | -0.5 | 0.0 | -0.1 | 0.4 | 0.4 | 0.2 | | 0.1 |
| Accounts payable | -0.4 | -9.2 | -12.5 | -13.3 | -4.8 | 2.2 | | 8.1 |
| Accrued compensation and benefits | -3.2 | -4.0 | -4.4 | -4.4 | -3.0 | -0.2 | | 0.1 |
| Other accrued expenses | 2.8 | 1.4 | 0.9 | -0.2 | 1.0 | 0.5 | 1.1 | 1.8 |
| Net cash provided by (used) in operating activities | 11.8 | 3.5 | -1.3 | -15.3 | -15.7 | -19.0 | -19.8 | -5.8 |
| |
| Cash flows from investing activities: | | | | | | | | |
| Purchases of marketable securities | -14.2 | -16.0 | -14.4 | -9.7 | -7.2 | -4.9 | -5.6 | |
| Maturities of marketable securities | 14.3 | 12.5 | 11.3 | 8.9 | 6.2 | 6.3 | | 7.3 |
| Purchase of property and equipment | -3.2 | -1.7 | -1.6 | -3.7 | -3.4 | -3.7 | -4.6 | -2.5 |
| Net cash used in investing activities | -9.8 | -10.4 | -9.9 | -7.6 | 7.2 | 8.7 | | 12.1 |
| |
| Cash flows from financing activities: | | | | | | | | |
| Proceeds from exercise of common stock options | 2.9 | 3.7 | 4.4 | 4.1 | 2.9 | 2.0 | | 1.3 |
| Taxes paid related to net share settlement of equity awards | | | | -1.0 | -0.8 | -0.4 | -0.1 | 0.0 |
| Net cash provided by financing activities | -0.4 | 0.1 | 0.4 | 1.1 | -1.5 | -2.7 | | -1.4 |
| Effect of exchange rate fluctuations on cash and cash equivalents | -0.1 | -0.1 | -0.1 | -0.1 | -0.1 | -0.1 | -0.2 | -0.1 |
| Net increase (decrease) in cash and cash equivalents | 1.5 | -6.9 | -10.9 | -9.5 | 2.4 | -0.6 | | 4.8 |
| Cash and cash equivalents at beginning of period | 36.7 | 40.4 | | 44.0 | 29.3 | 14.7 | | |
| Cash and cash equivalents at end of period | 38.2 | 33.4 | 33.1 | 34.6 | 31.8 | 14.0 | | 16.9 |
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| Supplemental disclosure of cash flow information: | | | | | | | | |
| Cash paid for income taxes | 0.5 | 0.4 | 0.3 | 0.2 | 0.1 | | | 0.0 |
| Cash from income tax refunds | | | 0.0 | 0.0 | 0.0 | | | |
| Cash paid for interest | 0.4 | 0.4 | 0.4 | 0.4 | 0.3 | 0.2 | | 0.3 |