| In millions, except per share items | Jun-30-23 | Mar-31-23 | Dec-31-22 | Sep-30-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 |
| | 10-Q | 8-K | 10-K | 10-Q | 10-Q | 10-Q | 10-K | 10-Q |
| Operating activities: | | | | | | | | |
| Net loss | -39.3 | | 0.0 | 35.9 | 0.4 | 24.7 | 0.0 | -253.2 |
| Adjustments to reconcile net loss to net cash used in operating activities: | | | | | | | | |
| Depreciation | 12.1 | | 14.3 | 15.1 | 15.0 | 15.3 | 15.5 | 15.3 |
| Amortization of right-of-use operating lease assets | 8.9 | | 5.4 | 2.5 | 2.2 | 1.9 | 1.7 | 1.5 |
| Amortization of other assets | 2.5 | | 2.4 | 2.4 | 2.4 | 2.4 | 2.4 | 2.3 |
| Amortization of premium (discount) on investments, net | -13.0 | | 7.4 | 13.3 | 16.8 | 17.9 | 17.8 | 17.2 |
| Amortization of debt issuance costs | 5.7 | | 5.4 | 5.4 | 5.5 | 5.4 | 5.0 | 4.5 |
| Stock-based compensation expense | 103.0 | | 100.3 | 96.8 | 103.5 | 109.1 | 120.7 | 193.5 |
| Loss (gain) on investments | -0.1 | | 0.2 | 0.1 | -0.2 | -1.1 | -1.1 | -6.8 |
| Gain on early retirement of debt | -11.3 | | | | | | | |
| Changes in operating assets and liabilities: | | | | | | | | |
| Contracts receivable | -21.0 | | 36.4 | 2.4 | 17.3 | -2.7 | 14.3 | 29.9 |
| Inventories | -5.7 | | 2.8 | 2.3 | 4.3 | -1.8 | -2.8 | -0.8 |
| Other current and long-term assets | -44.3 | | -24.7 | -12.2 | -10.1 | -24.6 | -0.9 | 6.0 |
| Accounts payable | 9.3 | | 1.1 | 10.3 | -5.9 | 6.4 | -6.0 | -2.5 |
| Accrued compensation | 4.3 | | 10.4 | -1.9 | -5.2 | -12.7 | -26.9 | 3.9 |
| Deferred contract revenue | -57.9 | | -71.2 | -66.6 | -73.4 | -84.1 | -82.8 | -73.6 |
| Net cash used in operating activities | -456.0 | | -274.4 | 129.5 | 98.4 | 53.8 | 30.8 | -74.9 |
| |
| Investing activities: | | | | | | | | |
| Purchases of short-term investments | -1,754.9 | | -1,485.8 | -1,417.0 | -1,046.7 | -1,257.0 | -1,124.2 | -1,124.7 |
| Proceeds from sale of short-term investments | 1,309.8 | | 989.2 | 1,056.4 | 996.7 | 1,111.1 | 1,344.2 | 1,440.4 |
| Purchases of property, plant and equipment | -32.2 | | -15.7 | -14.1 | -11.9 | -12.9 | -12.0 | -14.6 |
| Net cash used in investing activities | -227.9 | | -262.6 | -379.7 | -73.8 | -171.5 | 194.9 | 287.6 |
| |
| Financing activities: | | | | | | | | |
| Proceeds from equity, net | 7.9 | | 6.4 | 6.0 | 5.4 | 5.7 | 11.6 | 34.2 |
| Proceeds from issuance of 1.75 percent convertible senior notes | 575.0 | | | | | | | |
| Repurchase of $434.1 million principal amount of 0.125 percent convertible senior notes | -420.2 | | | | | | | |
| Proceeds from sale of future royalties | 500.0 | | | | | | | |
| Payments of transaction costs related to sale of future royalties | -10.4 | | | | | | | |
| Net cash provided by (used in) financing activities | 586.4 | | -55.3 | -66.8 | -67.1 | 246.2 | 245.9 | -213.1 |
| Effects of exchange rates on cash | 0.3 | | | | | | | |
| Net increase (decrease) in cash and cash equivalents | -444.4 | | -940.0 | | -347.3 | | | |
| |
| Supplemental disclosures of cash flow information: | | | | | | | | |
| Interest paid | 1.9 | | 2.9 | 3.5 | 3.5 | 4.8 | 4.8 | 6.1 |
| Supplemental disclosures of non-cash investing and financing activities: | | | | | | | | |
| Amounts accrued for capital and patent expenditures | 3.9 | | 4.8 | 1.9 | 1.5 | 0.2 | 0.7 | -0.7 |