| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Operating activities | | | | | | | | |
| Net loss | -93.0 | -97.9 | -52.5 | -40.0 | -29.4 | -40.8 | -53.0 | -120.8 |
| |
| Adjustments to reconcile net loss to net cash used in operating activities: | | | | | | | | |
| Equity-based compensation expense | 10.0 | 4.7 | 4.3 | 5.2 | 6.4 | 5.7 | 13.3 | 14.8 |
| Imputed interest expense on royalty financing obligation | 8.0 | | | | | | | |
| Depreciation and amortization | 2.0 | 0.5 | 0.5 | 0.5 | 0.6 | 0.7 | 0.8 | 1.0 |
| Other | -0.3 | -0.1 | -0.2 | 0.0 | 0.8 | 0.0 | | |
| Changes in operating assets and liabilities: | | | | | | | | |
| Accounts receivable, net | -15.4 | | | | | 0.4 | -0.2 | 1.6 |
| Inventories | -0.7 | | | | | 1.1 | 0.6 | -0.4 |
| Prepaid expenses and other assets | 0.5 | 2.3 | 2.3 | 1.1 | -0.2 | 0.3 | 1.6 | -0.4 |
| Accounts payable, accrued expenses and other liabilities | 7.7 | 5.6 | -4.7 | -7.0 | 0.9 | | | |
| Net cash used in operating activities | -81.2 | -84.9 | -42.2 | -27.8 | -39.8 | -39.3 | -76.7 | -95.2 |
| |
| Investing activities | | | | | | | | |
| Milestone payment to S*BIO Pte Ltd. | -25.0 | | | | | | | |
| Purchases of short-term investments | -88.9 | | -12.1 | -11.0 | -42.1 | | | |
| Proceeds from maturities of short-term investments | 40.0 | 12.0 | 2.5 | 39.2 | 11.6 | | | |
| Net cash (used in) provided by investing activities | -73.9 | 12.0 | -9.6 | 28.1 | -30.5 | 0.0 | -0.1 | -0.1 |
| |
| Financing activities | | | | | | | | |
| Cash paid for offering costs | | | | -0.3 | -0.3 | | | |
| Gross proceeds from offering | | | | | 64.2 | | | 15.1 |
| Repayment of Silicon Valley Bank debt | | -6.3 | -5.3 | -5.3 | -0.4 | -19.5 | -5.5 | -4.7 |
| Proceeds from stock option exercises | 4.9 | 0.4 | 0.1 | 0.0 | 0.1 | 0.0 | | |
| Proceeds from ESPP stock issuance | 1.4 | 0.3 | 0.1 | 0.0 | 0.1 | 0.0 | | |
| Net cash provided by financing activities | 120.0 | 97.9 | 61.1 | -5.6 | 63.5 | 39.0 | -7.4 | 152.0 |
| Net (decrease) increase in cash and cash equivalents | -35.0 | 25.1 | | | | | | |
| |
| Supplemental disclosure of cash flow information | | | | | | | | |
| Cash paid during the period for interest | 6.1 | 2.0 | 0.5 | 1.0 | 1.2 | 2.0 | 4.4 | 2.1 |
| |
| Supplemental disclosure of noncash financing and investing activities | | | | | | | | |
| Conversion of preferred stock to common stock | 32.5 | 6.4 | | | | | | |