SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”), reflect the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions between and among its consolidated subsidiaries have been eliminated. Management has determined that the Company operates in one segment: discovering, developing, manufacturing and delivering therapies to patients with rare diseases. In the opinion of the Company’s management, all adjustments of a normal recurring nature necessary for a fair presentation have been reflected. Certain financial information that is normally included in annual financial statements prepared in accordance with U.S. GAAP, but that is not required for interim reporting purposes, has been omitted. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes for the year ended December 31, 2021 which are contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021, filed with the U.S. Securities and Exchange Commission on March 1, 2022. The results for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the full year.
Estimates and Uncertainties	Estimates and Uncertainties The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenue, expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist of accounts receivable from customers, cash held at financial institutions and cash equivalents and investments. As of September 30, 2022, the majority of the Company’s accounts receivable arose from product sales in the U.S. and all customers have standard payment terms that generally require payment within 60 to 91 days. Outside of the U.S., the majority of the Company’s customers have payment terms ranging between 45 and 150 days. Three individual customers accounted for 48%, 35% and 7% of net product revenues for the three months ended September 30, 2022 and 49%, 34% and 7% of net product revenues for the nine months ended September 30, 2022. Three individual customers accounted for 45%, 39% and 11% of net product revenues for the three months ended September 30, 2021 and 47%, 40% and 10% of net product revenues for the nine months ended September 30, 2021. Three individual customers accounted for 39%, 36% and 9% of accounts receivable from product sales as of September 30, 2022 and 41%, 41% and 10% of accounts receivable from product sales as of December 31, 2021. The Company monitors the financial performance and creditworthiness of its customers so that it can properly assess and respond to changes in its customers’ credit profile. As of September 30, 2022, the Company believes that such customers are of high credit quality. As of September 30, 2022, the Company’s cash was concentrated at three financial institutions in the U.S., which potentially exposes the Company to credit risks. However, the Company does not believe that there is significant risk of non-performance by the financial institutions. The Company also purchases commercial paper, government and government agency bonds, corporate bonds and certificates of deposit issued by highly rated corporations, financial institutions and governments and limits the amount of credit exposure to any one issuer. These amounts may at times exceed federally insured limits. The Company has not experienced any credit losses related to these financial instruments and does not believe to be exposed to any significant credit risk related to these instruments.
Significant Accounting Policies	Significant Accounting Policies For details about the Company's accounting policies, please read Note 2, Summary of Significant Accounting Policies and Recent Accounting Pronouncements of the Annual Report on Form 10-K for the year ended December 31, 2021. There have not been any material changes to the Company's accounting policies through September 30, 2022.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

9 Months Ended

Sep. 30, 2022

The accompanying unaudited condensed consolidated financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”), reflect the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions between and among its consolidated subsidiaries have been eliminated. Management has determined that the Company operates in one segment: discovering, developing, manufacturing and delivering therapies to patients with rare diseases.

In the opinion of the Company’s management, all adjustments of a normal recurring nature necessary for a fair presentation have been reflected. Certain financial information that is normally included in annual financial statements prepared in accordance with U.S. GAAP, but that is not required for interim reporting purposes, has been omitted. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes for the year ended December 31, 2021 which are contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021, filed with the U.S. Securities and Exchange Commission on March 1, 2022. The results for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for the full year.

Estimates and Uncertainties

The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenue, expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist of accounts receivable from customers, cash held at financial institutions and cash equivalents and investments.

As of September 30, 2022, the majority of the Company’s accounts receivable arose from product sales in the U.S. and all customers have standard payment terms that generally require payment within 60 to 91 days. Outside of the U.S., the majority of the Company’s customers have payment terms ranging between 45 and 150 days. Three individual customers accounted for 48%, 35% and 7% of net product revenues for the three months ended September 30, 2022 and 49%, 34% and 7% of net product revenues for the nine months ended September 30, 2022. Three individual customers accounted for 45%, 39% and 11% of net product revenues for the three months ended September 30, 2021 and 47%, 40% and 10% of net product revenues for the nine months ended September 30, 2021. Three individual customers accounted for 39%, 36% and 9% of accounts receivable from product sales as of September 30, 2022 and 41%, 41% and 10% of accounts receivable from product sales as of December 31, 2021. The Company monitors the financial performance and creditworthiness of its customers so that it can properly assess and respond to changes in its customers’ credit profile. As of September 30, 2022, the Company believes that such customers are of high credit quality.

As of September 30, 2022, the Company’s cash was concentrated at three financial institutions in the U.S., which potentially exposes the Company to credit risks. However, the Company does not believe that there is significant risk of non-performance by the financial institutions. The Company also purchases commercial paper, government and government agency bonds, corporate bonds and certificates of deposit issued by highly rated corporations, financial institutions and governments and limits the amount of credit exposure to any one issuer. These amounts may at times exceed federally insured limits. The Company has not experienced any credit losses related to these financial instruments and does not believe to be exposed to any significant credit risk related to these instruments.

Significant Accounting Policies

For details about the Company's accounting policies, please read Note 2, Summary of Significant Accounting Policies and Recent Accounting Pronouncements of the Annual Report on Form 10-K for the year ended December 31, 2021.

There have not been any material changes to the Company's accounting policies through September 30, 2022.