Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2019

Accounting Policies [Abstract]

Schedule of Restricted Cash

Restricted Cash—

(in thousands)	As of September 30, 2019		As of December 31, 2018
Letter of credit security: Cambridge lease (a)	$	264	$	264
Letter of credit security: Waltham lease (b)	250		—
Letter of credit security: Vienna Austria lease (c)	91		—
Corporate credit card collateral (d)	150		100
Total restricted cash (non-current)	$	755	$	364

(a)In connection with the Company’s lease agreement for its facility in Cambridge, Massachusetts, the Company maintains a letter of credit of $264 thousand, which is secured by restricted cash, for the benefit of the landlord.

(b)In connection with the Company's lease agreement for a facility in Waltham, Massachusetts, the Company maintains a letter of credit of $250 thousand, which is secured by restricted cash for the benefit of the landlord.

(c)In connection with the Company’s lease agreement for its laboratory and office facility in Vienna, Austria, the Company maintains a letter of credit of $91 thousand, which is secured by restricted cash, for the benefit of the landlord.

(d)As of September 30, 2019, and December 31, 2018, the Company was required to maintain a separate cash balance of $150 thousand and $100 thousand, respectively, to collateralize corporate credit cards with a bank

Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed consolidated balance sheets to the sum to the total of amounts shown in the Company’s condensed consolidated statement of cash flows as of September 30, 2019, December 31, 2018 September 30, 2018 and December 31, 2017: 

(in thousands)	September 30, 2019		December 31, 2018		September 30, 2018		December 31, 2017
Cash and cash equivalents	$	76,251	$	8,134	$	9,840	$	26,684
Restricted cash, non-current	755		364		364		364
Total cash, cash equivalents and restricted cash	$	77,006	$	8,498	$	10,204	$	27,048

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization expense is recognized using the straight-line method over the estimated useful life of each asset, as follows:

	Estimated Useful Life
Office furniture	3 years
Computer equipment	3 years
Laboratory equipment	3 to 10 years
Leasehold improvements	Shorter of lease term or 10 years