| Fair Value, by Balance Sheet Grouping [Table Text Block] |
| | | June 30, 2024 | |
| | | (in thousands) | |
| | | Level 1 | | | Level 2 | | | Level 3 | | | Total | |
| Assets | | | | | | | | | | | | | | | | |
| Cash Equivalents: | | | | | | | | | | | | | | | | |
| Certificates of deposit (1) | | $ | — | | | $ | 1,504 | | | $ | — | | | $ | 1,504 | |
| Money market funds | | | — | | | | 4,136 | | | | — | | | | 4,136 | |
| U.S. treasury bills | | | — | | | | 176,739 | | | | — | | | | 176,739 | |
| Short term investments: | | | | | | | | | | | | | | | | |
| Certificates of deposit (1) | | | — | | | | 3,791 | | | | — | | | | 3,791 | |
| Other assets: | | | | | | | | | | | | | | | | |
| Notes receivables (3) | | | — | | | | — | | | | 2,690 | | | | 2,690 | |
| Total | | $ | — | | | $ | 186,170 | | | $ | 2,690 | | | $ | 188,860 | |
| Liabilities: | | | | | | | | | | | | | | | | |
| Earn-out shares liabilities: | | | | | | | | | | | | | | | | |
| Earn-out shares (2) | | $ | — | | | $ | — | | | $ | 25,613 | | | $ | 25,613 | |
| Other non-current liabilities: | | | | | | | | | | | | | | | | |
| Warrant liabilities (2) | | | — | | | | 705 | | | | — | | | | 705 | |
| Total | | $ | — | | | $ | 705 | | | $ | 25,613 | | | $ | 26,318 | |
| | | December 31, 2023 | |
| | | (in thousands) | |
| | | Level 1 | | | Level 2 | | | Level 3 | | | Total | |
| Assets | | | | | | | | | | | | | | | | |
| Cash Equivalents: | | | | | | | | | | | | | | | | |
| Certificates of deposit (1) | | $ | — | | | $ | 1,533 | | | $ | — | | | $ | 1,533 | |
| Money market funds | | | — | | | | 4,423 | | | | — | | | | 4,423 | |
| U.S. treasury bills | | | — | | | | 171,841 | | | | — | | | | 171,841 | |
| Short term investments: | | | | | | | | | | | | | | | | |
| Certificates of deposit (1) | | | — | | | | 3,721 | | | | — | | | | 3,721 | |
| Other assets: | | | | | | | | | | | | | | | | |
| Notes receivables (3) | | | — | | | | — | | | | 1,840 | | | | 1,840 | |
| Total | | $ | — | | | $ | 181,518 | | | $ | 1,840 | | | $ | 183,358 | |
| Liabilities: | | | | | | | | | | | | | | | | |
| Earn-out shares liabilities: | | | | | | | | | | | | | | | | |
| Earn-out shares (2) | | $ | — | | | $ | — | | | $ | 18,346 | | | $ | 18,346 | |
| Other non-current liabilities: | | | | | | | | | | | | | | | | |
| Warrant liabilities (2) | | | — | | | | 533 | | | | — | | | | 533 | |
| Total | | $ | — | | | $ | 533 | | | $ | 18,346 | | | $ | 18,879 | |
|
| Debt Securities, Available-for-Sale [Table Text Block] |
| | | June 30, 2024 | |
| | | (in thousands) | |
| | | Amortized Cost | | | Fair Value | | | Gross unrealized losses | |
| U.S. treasury bills | | $ | 176,780 | | | $ | 176,739 | | | $ | (41 | ) |
| Total | | $ | 176,780 | | | $ | 176,739 | | | $ | (41 | ) |
| | | December 31, 2023 | |
| | | (in thousands) | |
| | | Amortized Cost | | | Fair Value | | | Gross unrealized gains | |
| U.S. treasury bills | | $ | 171,815 | | | $ | 171,841 | | | $ | 26 | |
| Total | | $ | 171,815 | | | $ | 171,841 | | | $ | 26 | |
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