Property and equipment:	6 Months Ended
Jun. 30, 2021
Property and equipment:
Property and equipment:	2. Property and equipment: Depreciation and amortization expense related to property and equipment and finance leases was $22.1 million and $19.9 million for the three months ended June 30, 2021 and 2020 respectively, and $44.1 million and $39.4 million for the six months ended June 30, 2021 and 2020, respectively. The Company capitalized salaries and related benefits of employees working directly on the construction and build-out of its network of $4.2 million and $3.0 million for the three months ended June 30, 2021 and 2020, respectively, and $7.4 million and $5.9 million for the six months ended June 30, 2021 and 2020, respectively. Installment payment agreement The Company has entered into an installment payment agreement (“IPA”) with a vendor. Under the IPA the Company was able to purchase network equipment in exchange for interest free note obligations each with a twenty-four month term. There were no payments under each note obligation for the first six months followed by eighteen equal installment payments for the remaining eighteen month term until July 2020 when additional borrowings under the IPA expired. As of June 30, 2021 and December 31, 2020 there was $3.4 million and $7.7 million, respectively, of note obligations outstanding under the IPA, secured by the related equipment. The Company recorded the assets purchased and the net present value of the note obligation utilizing an imputed interest rate. The resulting discounts totaling $41,000 and $141,000 as of June 30, 2021 and December 31, 2020, respectively, are being amortized over the note term using the effective interest rate method.

Property and equipment:

6 Months Ended

Jun. 30, 2021

2. Property and equipment:

Depreciation and amortization expense related to property and equipment and finance leases was $22.1 million and $19.9 million for the three months ended June 30, 2021 and 2020 respectively, and $44.1 million and $39.4 million for the six months ended June 30, 2021 and 2020, respectively. The Company capitalized salaries and related benefits of employees working directly on the construction and build-out of its network of $4.2 million and $3.0 million for the three months ended June 30, 2021 and 2020, respectively, and $7.4 million and $5.9 million for the six months ended June 30, 2021 and 2020, respectively.

Installment payment agreement

The Company has entered into an installment payment agreement (“IPA”) with a vendor. Under the IPA the Company was able to purchase network equipment in exchange for interest free note obligations each with a twenty-four month term. There were no payments under each note obligation for the first six months followed by eighteen equal installment payments for the remaining eighteen month term until July 2020 when additional borrowings under the IPA expired. As of June 30, 2021 and December 31, 2020 there was $3.4 million and $7.7 million, respectively, of note obligations outstanding under the IPA, secured by the related equipment. The Company recorded the assets purchased and the net present value of the note obligation utilizing an imputed interest rate. The resulting discounts totaling $41,000 and $141,000 as of June 30, 2021 and December 31, 2020, respectively, are being amortized over the note term using the effective interest rate method.