Net Cash Provided by (Used in) Operating Activities
During the nine months ended September 30, 2024, we used $39.5 million of net cash in operating activities. Cash used in operating activities reflected a net loss of $52.0 million, partially offset by a net decrease in our operating assets of $1.5 million, and net non-cash charges of $11.0 million related to depreciation, amortization, share-based compensation, amortization of premium and discount, net, and impairment of long-lived assets. The primary use of cash was to fund our operations related to the development of our product candidates.
During the nine months ended September 30, 2023, we used $58.7 million of net cash in operating activities. Cash used in operating activities reflected a net loss of $85.3 million, partially offset by a net decrease in our operating assets of $9.6 million and net non-cash charges of $17.0 million primarily related to share-based compensation, depreciation, amortization, impairment of long-lived assets, and amortization of premium and discount, net. The primary use of cash was to fund our operations related to the development of our product candidates.
Net Cash Provided by (Used in) Investing Activities
During the nine months ended September 30, 2024, we purchased $72.6 million in marketable securities, and had sales and maturities of $113.9 million in marketable securities. Purchases of property and equipment were de minimus for the nine months ended September 30, 2024.
During the nine months ended September 30, 2023, we purchased $101.6 million in marketable securities, and had sales and maturities of $159.4 million in marketable securities. Purchases of property and equipment were $0.1 million for the nine months ended September 30, 2023.
Net Cash Provided by (Used in) Financing Activities
During the nine months ended September 30, 2024, we received $8.7 million in net proceeds from the issuance of common stock under the ATM Facility. We received gross proceeds of $9.0 million, net of offering costs of $0.3 million. We received $0.1 million in proceeds from the issuance of common stock under the ESPP and exercises of employee stock options.
During the nine months ended September 30, 2023, we received $0.1 million in proceeds from the issuance of common stock under the ESPP.
Contractual Obligations and Other Commitments
We lease approximately 37,000 square feet of office space in Philadelphia, Pennsylvania, or the 2005 Market Street Lease Agreement. The lease will expire in December 2031. We have an option to extend the term of the lease by up to two additional five-year terms. The aggregate estimated rent payments due over the initial term of the lease is $11.8 million, with rent payments that began in 2022. Our sublease agreements do not relieve us from our primary obligations under the 2005 Market Street Lease Agreement, however, we do expect cash inflows from the agreements to partially offset our future obligations for the duration of the sublease agreements.
We sublease approximately 16,000 square feet of office space in Philadelphia, Pennsylvania, or the 1835 Market Street Sublease Agreement. The sublease will expire in August 2025. We have an option to extend the term of the sublease by three and a half years through February 2029. The aggregate estimated rent payments due over the initial term of the sublease is approximately $0.5 million, with rent payments that began in 2024.
We lease approximately 62,000 square feet of laboratory space in Hopewell, New Jersey, or the Laboratory Lease Agreement. The lease will expire in March 2036. The aggregate estimated rent payments due over the initial term of the lease is approximately $40.3 million, with rent payments that began in 2021. Our sublease agreement does not relieve us from our primary obligations under the Laboratory Lease Agreement, however, we do expect cash inflows from the agreement to partially offset our future obligations for the duration of the sublease agreement.