The Company adopted ASC 842 on January 1, 2019 using the modified retrospective approach with no restatement of prior periods or cumulative adjustment to accumulated deficit. The reported results for 2019 reflect the application of ASC 842 while the reported results for 2018 and 2017 were prepared under ASC 840. Upon adoption, the Company elected the package of transition practical expedients, which allowed the Company to carry forward prior conclusions related to whether any expired or existing contracts are or contain leases, the lease classification for any expired or existing leases and initial direct costs for existing leases. The Company also made an accounting policy election not to recognize leases with an initial term of 12 months or less within its consolidated balance sheets and to recognize those lease payments on a straight-line basis in its consolidated statements of operations and comprehensive loss over the lease term. Upon adoption of the new leasing standards, the Company recognized an operating lease asset of approximately $13,737 and a corresponding operating lease liability of approximately $24,497, which are included in the Company’s consolidated balance sheet. The adoption of the new leasing standards did not have any impact on the Company’s consolidated statements of operations and comprehensive loss. The impact to the consolidated balance sheets for the opening balances is as follows:

	December 31, 2018		Impact of adoption of ASC 842			January 1, 2019
Operating lease assets	$	—	$	13,737		$	13,737
Accrued expenses and other current liabilities	$	15,207	$	(1,768	)	$	13,439
Operating lease liabilities	$	—	$	4,285		$	4,285
Lease incentive obligation, net of current portion	$	6,776	$	(6,776	)	$	—
Deferred rent	$	2,216	$	(2,216	)	$	—
Operating lease liabilities, net of current portion	$	—	$	20,212		$	20,212

The Company leases real estate, primarily laboratory, office and manufacturing space. The Company’s leases have remaining terms ranging from less than 1 year to 5 years. Certain leases include one or more options to renew, exercised at the Company’s sole discretion, with renewal terms that can extend the lease from one year to five years. The Company evaluated the renewal options in its leases to determine if it was reasonably certain that the renewal option would be exercised, and therefore should be included in the calculation of the operating lease assets and operating lease liabilities. Given the Company’s current business structure, uncertainty of future growth, and the associated impact to real estate, the Company concluded that it is not reasonably certain that any renewal options would be exercised. Therefore, the operating lease assets and operating lease liabilities only contemplate the initial lease terms. All of the Company’s leases qualify as operating leases.

In July 2019, the Company entered into a sublease agreement with a related party to sublease a portion of its office and laboratory space in Cambridge, Massachusetts. The term of the sublease agreement commenced in July 2019 and ends on the last day of the 24th calendar month following commencement, with no option to extend. The annual rent for the subleased premises will be approximately $1,200 in the first year and $1,300 in the second year, which is greater than the annual rent owed by the Company to the landlord for the leased premises. The sublessee is obligated to pay all real estate taxes and costs related to the subleased premises, including cost of operations, maintenance, repair, replacement and property management.

As of December 31, 2019, future undiscounted cash inflows under the sublease are as follows:

Year Ending December 31,
2020	$	1,248
2021		633
Total	$	1,881

The Company concluded that the sublease is an operating lease. Consistent with the Company’s policy election for lessor operating leases, each lease component and its associated non-lease components is accounted for as a single lease component.

The following table summarizes the presentation in the Company’s consolidated balance sheets of its operating leases:

	As of December 31, 2019
Assets:
Operating lease assets	$	11,356

Liabilities:
Operating lease liabilities	$	4,456
Operating lease liabilities, net of current portion		15,676
Total operating lease liabilities	$	20,132

The following table summarizes the effect of lease costs in the Company’s consolidated statement of operations and comprehensive loss:

	For the Year Ended
	December 31, 2019
Operating lease costs	$	4,532
Short-term lease costs		1,878
Variable lease costs		3,022
Sublease income		(890	)
Total lease costs	$	8,542

During the year ended December 31, 2019, the Company recognized $4,322 of rental expense related to office, laboratory, and manufacturing space. During the year ended December 31, 2019, the Company made cash payments of $6,514 for operating leases.

As of December 31, 2019, future payments of operating lease liabilities are as follows (in thousands):

	As of December 31, 2019
2020		6,302
2021		6,461
2022		6,390
2023		5,157
2024 and thereafter		—
Total future payments of operating lease liabilities	$	24,310
Less: imputed interest		(4,178	)
Present value of operating lease liabilities	$	20,132

As of December 31, 2019, the weighted average remaining lease term was 3.88 years and the weighted average incremental borrowing rate used to determine the operating lease liability was 11%.

The future minimum lease payments under the Company’s operating leases as of December 31, 2018, were as follows (in thousands):

	As of December 31, 2018
2019	$	6,342
2020		6,120
2021		6,221
2022		6,372
2023		5,158
2024 and thereafter		—
Total future minimum lease payments	$	30,213

During the years ended December 31, 2018 and 2017, the Company recognized $4,377 and 4,458, of rental expense, respectively, related to office, laboratory, and manufacturing space.