Cash flows used in operating activities
Net cash used in operating activities was $120.0 million for the six months ended June 30, 2021, consisting of a net loss of $132.1 million, a net increase in cash resulting from adjustments for non-cash and other reconciling items of $38.3 million and a net decrease in cash resulting from changes in operating assets and liabilities of $26.2 million.
Net cash used in operating activities was $108.4 million for the six months ended June 30, 2020, consisting of a net loss of $145.9 million, a net increase in cash resulting from adjustments for non-cash and other reconciling items of $46.1 million and a net decrease in cash resulting from changes in operating assets and liabilities of $8.6 million.
Cash flows provided by (used in) investing activities
Net cash provided by investing activities was $149.5 million for the six months ended June 30, 2021, consisting of cash inflows from the net purchase and maturities of marketable securities of $151.4 million and partially offset by $1.9 million used for the purchase of property and equipment.
Net cash used in investing activities was $108.2 million for the six months ended June 30, 2020, consisting primarily of cash outflows from the net purchase and maturities of marketable securities of $124.8 million and $19.9 million cash inflow from the sale of marketable securities.
Cash flows provided by financing activities
Net cash provided by financing activities was $94.0 million for the six months ended June 30, 2021, consisting of the sale of 7,705,000 ordinary shares for total net proceeds of $108.2 million and $2.9 million in proceeds from ESPP and share option purchases. These proceeds were partially offset by $10.7 million in principal payments on the Non-Recourse 2035 Notes and $6.3 million related to the repurchase of shares to satisfy tax withholding obligations.
Net cash provided by financing activities was $263.3 million for the six months ended June 30, 2020, consisting primarily of the sale of 5,500,000 ordinary shares for total net proceeds of $139.9 million and the issuance of our Non-Recourse 2035 Notes for total net proceeds of $374.7 million. A portion of the Non-Recourse 2035 Notes proceeds was used to repay, in full, the remaining $235.3 million outstanding balance of our Non-Recourse 2033 Notes and an $11.5 million redemption premium related to the payoff of the Non-Recourse 2033 Notes. In addition to the above, net cash inflow provided by financing activities was partially offset by the repurchase of shares to satisfy tax withholding obligations in the amount of $7.9 million.
Commitments and Contingencies
We indemnify our officers and directors for certain events or occurrences, subject to certain limits. We believe the fair value of these indemnification agreements is minimal. Accordingly, we have not recognized any liabilities relating to these agreements as of June 30, 2021.
Performance-Contingent Awards
We periodically grant performance-contingent awards to our employees. For the six months ended June 30, 2021, we recognized $0.6 million of aggregate share-based compensation expense and cash bonus expense related to these types of awards. As of June 30, 2021, the maximum remaining expense related to outstanding performance-contingent awards was $0.6 million which had performance expiration dates through June 2022.
Off-Balance Sheet Arrangements
There have been no material changes in our off-balance sheet arrangements from those set forth in our Annual Report on Form 10-K for the year ended December 31, 2020, filed with the SEC on February 26, 2021.
Contractual Obligations and Commercial Commitments
There have been no material changes in our contractual obligations and commercial commitments from those set forth in our Annual Report on Form 10-K for the year ended December 31, 2020, filed with the SEC on February 26, 2021.