Executive and other non-recurring separation costs. We have excluded costs associated with the resignation of our former Executive Officers in calculating our non-GAAP operating expenses and net income measures. We exclude these and other non-recurring employee separation costs because we believe that these items do not reflect future operating expenses;
Customer Relationship Management. We have excluded CRM system costs related to direct and incremental costs incurred in connection with our multi-phase implementation of a new CRM solution and the related technology infrastructure costs. We exclude these costs because we believe that these items do not reflect future operating expenses and will be inconsistent in amounts and frequency making it difficult to contribute to a meaningful evaluation of our operating performance;
Enterprise Resource Planning. We have excluded ERP system costs related to direct and incremental costs incurred in connection with our multi-phase implementation of a new ERP solution and the related technology infrastructure costs. We exclude these costs because we believe that these items do not reflect future operating expenses and will be inconsistent in amounts and frequency making it difficult to contribute to a meaningful evaluation of our operating performance; and
Non-recurring legal and litigation costs. We have excluded costs incurred related to third party litigation and disputes, that are of a non-recurring nature.
The Company believes that excluding all of the items above allows users of its financial statements to better review and assess both current and historical results of operations. In the three months ended December 31, 2020, our revenue was $49.9 million, as compared to $51.8 million for the three months ended December 31, 2019. In the three months ended December 31, 2020, our gross profit on a non-GAAP basis was $28.3 million as compared to $29.4 million for the three months ended December 31, 2019, which, when calculated on a GAAP basis, would be equivalent to $28.1 million and $28.8 million, respectively. In the three months ended December 31, 2020, our income from operations on a non-GAAP basis was $4.7 million as compared to $2.1 million for the three months ended December 31, 2019, which, when calculated on a GAAP basis, would be equivalent to $1.4 million profit and $1.9 million loss, respectively. Our cash balance at December 31, 2020 was $47.0 million.
When calculating our gross profit on a non-GAAP basis, for the three months ended December 31, 2020, we excluded $0.3 million in stock-based compensation, $0.2 million in depreciation and amortization, and $0.3 million in taxes and other adjustments. When calculating our income from operations on a non-GAAP basis, for the three months ended December 31, 2020, we excluded $2.1 million in stock-based compensation, $0.9 million in depreciation and amortization, $0.6 million in non-recurring legal expenses and $0.3 million in taxes and other adjustments
In the twelve months ended December 31, 2020, our revenue was $147.7 million, as compared to $181.7 million for the twelve months ended December 31, 2019. In the twelve months ended December 31, 2020, our gross profit on a non-GAAP basis was $78.1 million as compared to $100.3 million for the twelve months ended December 31, 2019, which, when calculated on a GAAP basis, would be equivalent to $75.8 million and $98.2 million, respectively. In the twelve months ended December 31, 2020, our loss from operations on a non-GAAP basis was $4.8 million as compared to a profit of $4.3 million for the twelve months ended December 31, 2019, which, when calculated on a GAAP basis, would be equivalent to losses of $22.8 million and $12.1 million, respectively.
When calculating our gross profit on a non-GAAP basis, for the twelve months ended December 31, 2020, we excluded approximately $1.7 million in stock-based compensation, $0.6 million in depreciation and amortization, $0.3 million in severance and $0.3 million in taxes and other adjustments. When calculating our loss from operations on a non-GAAP basis, for the twelve months ended December 31, 2020, we excluded approximately $10.1 million in stock-based compensation, $4.0 million in depreciation and amortization, $1.1 million in implementation costs for our CRM and ERP systems, $0.8 million in severance, and $1.9 million in non-recurring legal expenses.”