Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2021
Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of Collegium Pharmaceutical, Inc. (a Virginia corporation) as well as the accounts of Collegium Securities Corp. (a Massachusetts corporation), incorporated in December 2015, and Collegium NF, LLC (a Delaware limited liability company), organized in December 2017, both wholly owned subsidiaries requiring consolidation. The consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. In the opinion of the Company’s management, the accompanying unaudited Condensed Consolidated Financial Statements contain all adjustments (consisting of items of a normal and recurring nature) necessary to fairly present the financial position of the Company as of March 31, 2021, and the results of operations and cash flows for the three months ended March 31, 2021 and 2020. The results of operations for the three months ended March 31, 2021 are not necessarily indicative of the results to be expected for the full year. The preparation of the Condensed Consolidated Financial Statements in accordance with GAAP requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues, costs and expenses and the disclosure of contingent assets and liabilities in the Company’s consolidated financial statements and accompanying notes. Estimates in the Company’s consolidated financial statements include revenue recognition, including the estimates of product returns, units prescribed, discounts and allowances related to commercial sales of products, estimates of useful lives with respect to intangible assets, accounting for stock-based compensation, contingencies, impairment of intangible assets and tax valuation allowances. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. The Company evaluates its estimates and assumptions on an ongoing basis. The Company’s actual results may differ from these estimates under different assumptions or conditions. The consolidated interim financial statements should be read in conjunction with the audited financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020 (the “Annual Report”).
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In August 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Updated (“ASU”) 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity. This ASU simplifies the complexity associated with applying U.S. GAAP for certain financial instruments with characteristics of liabilities and equity. More specifically, the amendments focus on the guidance for convertible instruments and derivative scope exceptions for contracts in an entity’s own equity. Under ASU 2020-06, the embedded conversion features are no longer separated from the host contract for convertible instruments with conversion features that are not required to be accounted for as derivatives under Topic 815, or that do not result in substantial premiums accounted for as paid-in capital. Consequently, a convertible debt instrument, such as the Company’s convertible senior notes, will be accounted for as a single liability measured at its amortized cost, as long as no other features require bifurcation and recognition as derivatives. The new guidance also requires the if-converted method to be applied for all convertible instruments and requires additional disclosures. This guidance is required to be adopted by January 1, 2022, and early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020. The Company elected to early adopt this guidance on January 1, 2021 using the modified retrospective method. Under this transition method, the cumulative effect of the accounting change was removing the impact of recognizing the equity component of the Company’s convertible notes (at issuance and the subsequent accounting impact of additional interest expense from debt discount amortization). The cumulative effective of the accounting change as of January 1, 2021 was an increase to the carrying amount of the convertible notes of $39,489, a reduction to accumulated deficit of $5,288, and a reduction to additional paid-in capital of $44,777. Interest expense of the convertible senior notes will be lower as a result of adoption of this guidance and diluted net loss per share will be computed using the if-converted method for the convertible senior notes. As a result of the adoption of this guidance, interest expense was decreased by and net income was increased by $1,552 for the three months ended March 31, 2021, and diluted earnings per share was increased by $0.02 per share. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments in ASU 2019-12 affect a wide variety of income tax accounting standards with the objective of reducing their complexity. The new standard became effective for annual and interim periods beginning after December 15, 2020. The Company adopted this standard during the three months ended March 31, 2021 and the adoption did not have a material impact on the Company’s condensed consolidated financial statements. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, to ease the potential burden in accounting for reference rate reform. The amendments in ASU 2020-04 are elective and apply to all entities that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. The new standard became effective immediately and may be applied prospectively to contracts and transactions through December 31, 2022. Subsequent to issuance, the FASB issued ASU 2021-01 in January 2021 to refine and clarify some its guidance on ASU 2020-04. Upon the transition of the Company’s contracts and transactions to new reference rates in connection with reference rate reform, the Company will prospectively apply the standard and disclose the effect on its condensed consolidated financial statements. Recently Issued Accounting Pronouncements Not Yet Adopted Other recent accounting pronouncements issued, but not yet effective, are not expected to be applicable to the Company or have a material effect on the consolidated financial statements upon future adoption.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2021

Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of Collegium Pharmaceutical, Inc. (a Virginia corporation) as well as the accounts of Collegium Securities Corp. (a Massachusetts corporation), incorporated in December 2015, and Collegium NF, LLC (a Delaware limited liability company), organized in December 2017, both wholly owned subsidiaries requiring consolidation. The consolidated financial

statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by GAAP for complete consolidated financial statements.

In the opinion of the Company’s management, the accompanying unaudited Condensed Consolidated Financial Statements contain all adjustments (consisting of items of a normal and recurring nature) necessary to fairly present the financial position of the Company as of March 31, 2021, and the results of operations and cash flows for the three months ended March 31, 2021 and 2020. The results of operations for the three months ended March 31, 2021 are not necessarily indicative of the results to be expected for the full year.

The preparation of the Condensed Consolidated Financial Statements in accordance with GAAP requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues, costs and expenses and the disclosure of contingent assets and liabilities in the Company’s consolidated financial statements and accompanying notes. Estimates in the Company’s consolidated financial statements include revenue recognition, including the estimates of product returns, units prescribed, discounts and allowances related to commercial sales of products, estimates of useful lives with respect to intangible assets, accounting for stock-based compensation, contingencies, impairment of intangible assets and tax valuation allowances. The Company bases estimates and assumptions on historical experience when available and on various factors that it believes to be reasonable under the circumstances. The Company evaluates its estimates and assumptions on an ongoing basis. The Company’s actual results may differ from these estimates under different assumptions or conditions. The consolidated interim financial statements should be read in conjunction with the audited financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020 (the “Annual Report”).

Recently Adopted Accounting Pronouncements

Recently Adopted Accounting Pronouncements

In August 2020, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Updated (“ASU”) 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity. This ASU simplifies the complexity associated with applying U.S. GAAP for certain financial instruments with characteristics of liabilities and equity. More specifically, the amendments focus on the guidance for convertible instruments and derivative scope exceptions for contracts in an entity’s own equity. Under ASU 2020-06, the embedded conversion features are no longer separated from the host contract for convertible instruments with conversion features that are not required to be accounted for as derivatives under Topic 815, or that do not result in substantial premiums accounted for as paid-in capital. Consequently, a convertible debt instrument, such as the Company’s convertible senior notes, will be accounted for as a single liability measured at its amortized cost, as long as no other features require bifurcation and recognition as derivatives. The new guidance also requires the if-converted method to be applied for all convertible instruments and requires additional disclosures. This guidance is required to be adopted by January 1, 2022, and early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020.

The Company elected to early adopt this guidance on January 1, 2021 using the modified retrospective method. Under this transition method, the cumulative effect of the accounting change was removing the impact of recognizing the equity component of the Company’s convertible notes (at issuance and the subsequent accounting impact of additional interest expense from debt discount amortization). The cumulative effective of the accounting change as of January 1, 2021 was an increase to the carrying amount of the convertible notes of $39,489, a reduction to accumulated deficit of $5,288, and a reduction to additional paid-in capital of $44,777. Interest expense of the convertible senior notes will be lower as a result of adoption of this guidance and diluted net loss per share will be computed using the if-converted method for the convertible senior notes. As a result of the adoption of this guidance, interest expense was decreased by and net income was increased by $1,552 for the three months ended March 31, 2021, and diluted earnings per share was increased by $0.02 per share.

In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments in ASU 2019-12 affect a wide variety of income tax accounting standards with the objective of reducing their complexity. The new standard became effective for annual and interim periods beginning after December 15, 2020. The Company adopted this standard during the three months ended March 31, 2021 and the adoption did not have a material impact on the Company’s condensed consolidated financial statements.

In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, to ease the potential burden in accounting for reference rate reform. The amendments in ASU 2020-04 are elective and apply to all entities that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. The new standard became effective immediately and may be applied prospectively to contracts and transactions through December 31, 2022. Subsequent to issuance, the FASB issued ASU 2021-01 in January 2021 to refine and clarify some its guidance on ASU 2020-04. Upon the transition of the Company’s contracts and transactions to new reference rates in connection with reference rate reform, the Company will prospectively apply the standard and disclose the effect on its condensed consolidated financial statements.

Recently Issued Accounting Pronouncements Not Yet Adopted

Other recent accounting pronouncements issued, but not yet effective, are not expected to be applicable to the Company or have a material effect on the consolidated financial statements upon future adoption.