| In millions, except per share items | Jun-30-21 | Mar-31-21 | Dec-31-20 | Sep-30-20 | Jun-30-20 | Mar-31-20 | Dec-31-19 | Sep-30-19 |
| | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K | 10-Q |
| Cash flows from operating activities: | | | | | | | | |
| Net loss | -13.2 | -11.8 | -11.9 | -3.2 | -17.3 | -12.7 | -9.0 | -13.8 |
| Adjustments to reconcile net loss income to net cash used in operating activities: | | | | | | | | |
| Stock-based compensation | 2.1 | 2.3 | 1.8 | 2.1 | 1.8 | 1.8 | 1.5 | 2.2 |
| Amortization of intangible asset | 1.3 | 1.3 | 1.3 | 1.3 | 1.3 | 1.3 | 1.3 | 1.3 |
| Change in fair value of warrant liability | -0.7 | 0.8 | 1.0 | -6.9 | 7.4 | -0.6 | -1.3 | -3.2 |
| Amortization of debt discounts and debt issuance costs | 0.3 | 0.3 | 0.3 | 0.4 | | | | |
| Accretion of discounts on marketable securities | | | | | 0.0 | 0.0 | -0.1 | -0.2 |
| Depreciation | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Changes in operating assets and liabilities: | | | | | | | | |
| Accounts receivable | -0.7 | 0.0 | 0.1 | 0.0 | -0.2 | -0.4 | 1.1 | 3.0 |
| Inventory | 0.3 | -0.9 | 0.6 | 0.2 | 0.2 | 0.1 | 0.4 | 0.8 |
| Prepaid expenses and other current assets | 0.2 | -1.0 | 0.5 | 0.5 | -0.8 | 0.1 | 0.9 | 0.4 |
| Other assets | 0.1 | 0.1 | -0.2 | -0.1 | 0.0 | 0.3 | 0.2 | 0.2 |
| Accounts payable | -5.1 | 4.3 | -0.1 | -0.4 | -3.3 | 2.0 | 1.4 | 0.5 |
| Accrued and other liabilities | 5.7 | -8.6 | 1.7 | 0.4 | -1.2 | -6.9 | 2.1 | 2.2 |
| Net cash used in operating activities | -9.8 | -13.4 | -5.0 | -5.8 | -12.1 | -15.2 | -1.6 | -6.7 |
| |
| Cash flows from investing activities: | | | | | | | | |
| Sales and maturities of marketable securities | | | | | 6.3 | 14.8 | | |
| Purchases of property and equipment | | 0.0 | | 0.0 | | | 0.0 | 0.0 |
| Net cash (used in) provided by investing activities | | 0.0 | | 0.0 | 6.3 | 14.8 | 19.6 | -12.4 |
| |
| Cash flows from financing activities: | | | | | | | | |
| Payments related to tax withholding for net-share settled equity awards | -0.3 | -0.4 | | -0.1 | -0.3 | -0.1 | | 0.0 |
| Proceeds from long-term debt, net | | | 10.0 | -0.1 | 9.5 | | | |
| Proceeds from exercise of stock options | | 0.1 | | | | | | 0.0 |
| Proceed from issuance of ordinary shares in connection with at-the-market offering, net | | 0.0 | | | | | | |
| Net cash (used in) provided by financing activities | -0.3 | -0.2 | 10.7 | 27.7 | 9.2 | -0.1 | | 0.0 |
| Net (decrease) increase in cash and cash equivalents | -23.7 | | | | 2.9 | | | |
| |
| Supplemental disclosures of cash flow information: Cash paid during the year for: | | | | | | | | |
| Interest | 0.5 | 0.5 | 0.3 | 0.3 | 0.1 | | | |
| Income taxes other, net of refunds | | 1.3 | 0.0 | 0.2 | 0.5 | | | |