| 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-K | 10-K | 10-K | 10-K | 10-K |
| Operating activities | | | | | | | | |
| Net loss | -304.2 | -75.4 | -253.1 | | | | | |
| |
| Adjustments to reconcile net loss to net cash (used in) from operating activities: | | | | | | | | |
| Depreciation and amortization | 30.7 | 34.6 | 44.3 | 48.5 | 54.5 | 50.9 | 47.5 | 44.9 |
| Amortization of debt issuance costs and original issue discount | 1.5 | 0.7 | 1.1 | | | | | |
| Provision for doubtful accounts | 0.7 | 0.6 | 0.6 | 0.9 | 1.9 | 0.5 | 0.4 | 0.0 |
| Deferred income taxes | -1.1 | 0.9 | -2.1 | -50.5 | -56.8 | 24.4 | 10.1 | 11.2 |
| Lower of cost or net realizable value inventory adjustments | 4.3 | | | 1.5 | 4.5 | 5.4 | | |
| Loss (gain) on disposal or impairment of assets | 224.9 | -1.1 | 125.8 | 0.9 | 44.1 | 15.1 | 0.0 | 0.5 |
| Loss on sale of business | | | | | | | | |
| Noncash lease expense | -0.9 | | | | | | | |
| Stock compensation expense | 2.9 | 3.6 | 4.9 | 5.9 | 7.5 | 7.5 | 5.8 | 5.3 |
| Repayment of PIK accrual on notes payable, related parties | -2.0 | | | | | | | |
| Change in fair value of derivative instruments | | -2.5 | -0.9 | -7.7 | 11.2 | | | |
| Changes in operating assets and liabilities: | | | | | | | | |
| Trade accounts and other receivables | 21.6 | 1.5 | -20.5 | 24.6 | 81.4 | -9.5 | -22.0 | 8.9 |
| Inventories | 12.2 | 14.2 | 10.5 | 6.4 | 27.0 | -25.6 | 6.1 | -7.6 |
| Prepaid expenses, other current assets, and right of use assets | 2.3 | 0.7 | | | | | | |
| Accounts payable | -4.7 | -8.8 | 11.7 | 0.6 | -7.9 | 2.1 | 4.3 | -18.2 |
| Accrued expenses | 1.2 | 3.7 | 8.7 | -8.4 | -9.1 | -2.5 | 1.7 | -10.6 |
| Income tax receivable, net | -0.8 | 0.1 | -0.4 | 36.1 | 19.8 | -17.7 | -2.8 | 5.4 |
| Other, net | 0.0 | 3.2 | 2.9 | 1.7 | 0.7 | | | |
| Net cash used in operating activities | -11.5 | -21.6 | -38.8 | | | | | |
| |
| Investing activities | | | | | | | | |
| Capital expenditures | -2.2 | -2.0 | | | | | -99.9 | -77.2 |
| |
| Investment in PicOnyx | | | | | | | | |
| Issuance of Note from PicOnyx | | | | | | | | |
| Payment of Millen sale post-closing matters | -1.5 | | | | | | | |
| Net proceeds from asset sales | 1.1 | 27.5 | 21.6 | -6.8 | -62.7 | -161.5 | | |
| Net cash (used in) provided by investing activities | -4.3 | 25.5 | 19.0 | | | | | |
| |
| Financing activities | | | | | | | | |
| Proceeds from issuance of common stock under ATM program | | | | | | | | |
| Repayments on long-term debt | -14.5 | | -3.3 | -32.1 | -7.0 | | | |
| Proceeds from long-term debt | 14.5 | | 12.3 | | 70.0 | 25.0 | | |
| Repayments on notes payable | -2.7 | -1.4 | | | | | | |
| Repayments on notes payable, related parties | -25.0 | | | | | | | |
| Payment of debt issuance costs | -0.2 | | -1.0 | -0.3 | | | | |
| Purchase of common stock | -0.3 | -0.4 | -0.5 | -0.5 | -0.6 | -7.0 | -7.0 | -7.9 |
| Net cash (used in) provided by financing activities | -23.6 | 1.0 | 6.3 | | | | | |
| Net (decrease) increase in cash and cash equivalents and restricted cash | -39.3 | 4.9 | | | | | | |
| |
| Supplemental cash flow information | | | | | | | | |
| Interest paid | 6.8 | 7.7 | 2.3 | 5.3 | 2.6 | 0.1 | 0.0 | 0.1 |
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| Income taxes paid | | | | | | | | |