Nature of Operations and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Description and Basis of Presentation [Text Block]	Description of Business and Basis of Presentation Trupanion, Inc. (collectively with its wholly-owned subsidiaries, the Company) provides medical insurance for cats and dogs throughout the United States, Canada and Puerto Rico. The financial data as of December 31, 2019 was derived from the Company's audited consolidated financial statements. The accompanying unaudited interim consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and, in management's opinion, have been prepared on the same basis as the audited financial statements and include all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company's financial position, results of operations, comprehensive income (loss), stockholders' equity and cash flows for the interim periods. These unaudited interim consolidated financial statements should be read in conjunction with the Company’s audited financial statements included in the Company’s Annual Report on Form 10-K, filed with the U.S. Securities and Exchange Commission (SEC) on February 13, 2020 (the 2019 10-K). The Company's accounting policies are described in Note 1 to the audited financial statements included in the 2019 10-K. Operating results for the three and nine months ended September 30, 2020 are not necessarily indicative of the results that may be expected for the full fiscal year or any other interim period. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from such estimates. See Note 1 to the audited financial statements included in the 2019 10-K for additional discussion of these estimates and assumptions.
Basis of Accounting, Policy [Policy Text Block]	The financial data as of December 31, 2019 was derived from the Company's audited consolidated financial statements. The accompanying unaudited interim consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and, in management's opinion, have been prepared on the same basis as the audited financial statements and include all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company's financial position, results of operations, comprehensive income (loss), stockholders' equity and cash flows for the interim periods. These unaudited interim consolidated financial statements should be read in conjunction with the Company’s audited financial statements included in the Company’s Annual Report on Form 10-K, filed with the U.S. Securities and Exchange Commission (SEC) on February 13, 2020 (the 2019 10-K). The Company's accounting policies are described in Note 1 to the audited financial statements included in the 2019 10-K. Operating results for the three and nine months ended September 30, 2020 are not necessarily indicative of the results that may be expected for the full fiscal year or any other interim period.
Use of Estimates [Policy Text Block]	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from such estimates. See Note 1 to the audited financial statements included in the 2019 10-K for additional discussion of these estimates and assumptions.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Adopted Accounting Pronouncements The Company adopted Accounting Standards Update (ASU) 2016-13, Financial Instruments—Credit Losses (Topic 326), using the modified retrospective approach on January 1, 2020. The ASU replaces the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires the use of a forward-looking expected credit loss model for accounts receivables, loans, and other financial instruments. The new standard did not have a material impact on the Company's consolidated statements of operations, balance sheets, stockholders' equity, or cash flows. The Company did not record any cumulative-effect adjustment to its retained earnings upon the adoption.