| In millions, except per share items | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Cash Flows from Operating Activities | | | | | | | | |
| Net income (loss) | -21.8 | -61.4 | -49.7 | -30.9 | -22.5 | -27.1 | -27.1 | -4.2 |
| |
| Adjustments to reconcile net income (loss) to net cash from (used in) operating activities: | | | | | | | | |
| Stock-based compensation expense | 7.6 | 7.4 | 6.3 | 5.2 | 3.6 | 4.2 | 4.4 | 0.9 |
| Depreciation and amortization expense | 4.7 | 2.5 | 0.8 | 0.5 | 0.2 | 0.1 | 0.1 | |
| Gain on disposal of property and equipment | 0.1 | 0.2 | 0.0 | 0.0 | 0.0 | | | |
| Amortization of discount on marketable securities | 0.0 | -0.5 | -0.2 | 0.2 | | | | |
| Amortization of debt discount of loan payable | 0.3 | 0.1 | | | | | | |
| Finished goods write off related to Dechra asset purchase | 3.8 | | | | | | | |
| Changes in operating assets and liabilities: | | | | | | | | |
| Accounts receivable | 0.4 | 0.0 | -0.9 | | | | | |
| Inventories | 0.2 | -0.6 | -3.6 | | | | | |
| Prepaid expenses and other | -0.9 | -0.8 | -0.9 | 0.5 | -0.6 | -0.2 | -0.3 | -0.1 |
| Accounts payable | -1.2 | 1.8 | 0.3 | 1.3 | -0.7 | 0.0 | -0.3 | 0.7 |
| Accrued liabilities and accrued compensation | -3.0 | -5.0 | 2.8 | 1.4 | 1.0 | 0.1 | 1.3 | 1.2 |
| Net cash provided by (used in) operating activities | -9.9 | -56.3 | -45.0 | -21.9 | -18.8 | -22.8 | -21.9 | -1.6 |
| |
| Cash Flows from Investing Activities | | | | | | | | |
| Purchases of investments | -75.7 | -125.0 | -25.1 | -70.1 | -72.0 | -102.2 | -145.2 | |
| Sales of investments | | 3.0 | 0.8 | 4.9 | | 3.0 | 9.0 | |
| Maturities of investments | 85.0 | 82.6 | 54.6 | 68.5 | 78.3 | 129.4 | 48.0 | |
| Purchases of property and equipment | -3.6 | -8.4 | -13.9 | -5.9 | -1.0 | -0.7 | -0.4 | 0.0 |
| Proceeds from sale of property and equipment | 0.1 | 0.0 | 0.2 | | | | | |
| Net cash provided by investing activities | 5.8 | -47.8 | 16.6 | -2.7 | 5.3 | 29.4 | -88.6 | 0.0 |
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| Cash Flows from Financing Activities | | | | | | | | |
| Exercises of stock options and purchase of ESPP shares | 0.4 | 2.0 | 1.0 | 0.5 | 0.2 | 0.3 | 0.1 | 0.0 |
| Payment of restricted stock tax liability on net settlement | -0.9 | -0.5 | -0.2 | | | | | |
| Net proceeds from sale of common stock | 0.2 | 43.1 | 49.2 | 52.2 | | | 58.1 | 54.9 |
| Net cash provided by (used in) financing activities | -0.3 | 63.8 | 49.9 | 52.7 | 0.2 | 0.3 | 58.2 | 66.0 |
| Net change in cash and cash equivalents | -4.4 | -40.3 | 21.5 | 28.1 | | | | |
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| Supplemental disclosure of non-cash investing and financing activities: | | | | | | | | |
| Purchases of property and equipment included in accounts payable and accrued liabilities | 0.1 | 1.3 | 6.2 | 0.3 | 0.7 | 0.3 | | |