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Summary of Significant Accounting Policies (Tables) | 3 Months Ended
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Mar. 31, 2021
Summary Of Significant Accounting Policies [Line Items] |
Schedule of allowances for credit losses | ​
​ | ​ | ​ | ​
​ | ​ | Three months ended
​ |  | March 31,
​ | ​ | 2021
​ | ​ | ​ | (in thousands)
Beginning balance | ​ | $ | 4,220
Write-offs | ​ | ​ | (110)
Total | ​ | $ | 4,110
​ | ​ | ​ | ​
Schedule of Accumulated Other Comprehensive Income (Loss) | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | Three months ended | ​
​ | March 31, | ​
​ | 2021 | ​ | 2020 | ​
​ | (in thousands) | ​
Beginning balance | $ | 4,259 | ​ | $ | 919 | ​
Net unrealized gain (loss) on available-for-sale securities, net of tax | ​ | (1,062) | ​ | ​ | 4,747 | ​
Ending balance | $ | 3,197 | ​ | $ | 5,666 | ​
Accounting Standards Update 2020-06 |
Summary Of Significant Accounting Policies [Line Items] |
Schedule of new accounting pronouncements and changes in accounting principle | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | December 31, | ​ | ASU 2020-06 | ​ | January 1,
​ | 2020 | ​ | Adoption Adjustment | ​ | 2021
​ | (in thousands)
Liabilities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Outstanding Principal | $ | 287,500 | ​ | $ | — | ​ | $ | 287,500
Unamortized debt discount and issuance cost | ​ | (85,007) | ​ | ​ | 76,674 | ​ | ​ | (8,333)
Net carrying amount | $ | 202,493 | ​ | $ | 76,674 | ​ | $ | 279,167
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Equity | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Additional paid-in-capital | $ | (1,411,286) | ​ | $ | 82,872 | ​ | $ | (1,328,414)
Accumulated deficit | ​ | (929,318) | ​ | ​ | 6,198 | ​ | ​ | (923,120)

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- Definition Tabular disclosure of the various types of trade accounts and notes receivable and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date. Presentation is categorized by current, noncurrent and unclassified receivables. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3,4) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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