| In millions, except per share items | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 | Dec-31-12 |
| | 10-K | 10-K | 10-K | 10-Q/A | 10-K | 10-K | 10-K | 10-K |
| ASSETS | | | | | | | | |
| Current assets: | | | | | | | | |
| Cash and cash equivalents | 15.5 | 9.7 | 26.7 | 66.0 | 87.2 | 158.9 | 2.1 | 2.5 |
| Restricted cash | 0.2 | 2.9 | | | | | | |
| Accounts receivable, net | 20.4 | 16.1 | 12.7 | 21.7 | 14.0 | 14.4 | 4.9 | 1.6 |
| Inventories | 23.0 | 16.3 | 16.1 | 12.7 | 9.0 | 2.8 | 2.9 | 1.8 |
| Prepaid expenses and other receivables | 2.5 | 3.4 | 3.6 | 2.8 | 6.6 | 1.2 | 0.6 | |
| Total current assets | 61.6 | 48.4 | 59.1 | 103.3 | 116.8 | 177.2 | 10.6 | 6.1 |
| Intangible assets, net | 44.6 | 48.4 | 56.0 | 52.5 | 54.3 | 10.6 | | |
| Goodwill | 0.5 | 0.5 | 0.5 | 0.4 | 0.4 | | | |
| Other assets | 3.8 | 1.9 | 0.6 | 0.8 | 0.5 | 0.9 | 0.4 | 0.1 |
| Total assets | 206.9 | 190.9 | 184.6 | 183.2 | 180.7 | 197.1 | 15.4 | 9.4 |
| |
| LIABILITIES AND STOCKHOLDERS’ DEFICIT | | | | | | | | |
| Current liabilities: | | | | | | | | |
| Accounts payable | 6.9 | 5.9 | 10.6 | 4.6 | 4.0 | 1.6 | 1.5 | 1.1 |
| Accrued expenses | 9.3 | 9.8 | 8.1 | 10.3 | 6.3 | 5.1 | 2.9 | 0.8 |
| Capital lease obligation, current | 0.4 | | | | 0.1 | 0.1 | 0.0 | 0.0 |
| Total current liabilities | 16.6 | 32.6 | 18.7 | 15.0 | 10.8 | 13.0 | 5.2 | 2.0 |
| Senior Convertible Notes | 21.8 | | 121.0 | 111.4 | 103.0 | 100.3 | | |
| Revolver, net of debt issuance costs | 25.0 | 15.0 | | | | | | |
| 2023 Term Loans, net of debt issuance costs | 86.5 | 67.7 | | | | | | |
| Derivative liabilities | 6.8 | | | | | | | |
| Deferred tax liability | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | | | |
| Other long term liabilities | 2.3 | 0.1 | | | | 0.1 | 0.0 | |
| Total liabilities | 212.2 | 172.5 | 139.8 | 126.6 | 114.0 | 157.9 | 8.2 | 3.0 |
| |
| Commitments and Contingencies | | | | | | | | |
| Mezzanine equity: | | | | | | | | |
| |
| Stockholders’ deficit: | | | | | | | | |
| Common stock | 0.6 | 0.6 | 0.6 | 0.6 | 0.5 | 0.5 | 0.5 | 0.4 |
| Additional paid-in capital | 118.0 | 116.9 | 106.3 | 102.6 | 99.3 | 78.2 | 51.5 | 47.4 |
| Accumulated deficit | -121.5 | -96.4 | -60.1 | -44.9 | -32.9 | -39.6 | -44.8 | -43.4 |
| Accumulated other comprehensive loss, net of taxes | -2.4 | -2.7 | -2.0 | -1.6 | -0.1 | | | |
| Total stockholders’ deficit | -5.3 | 18.4 | 44.8 | 56.7 | 66.8 | 39.1 | 7.2 | 6.4 |
| Total liabilities, mezzanine equity and stockholders' deficit | 206.9 | 190.9 | 184.6 | 183.2 | 180.7 | 197.1 | 15.4 | 9.4 |