Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Recently Adopted Accounting Pronouncements

Summary of property plant 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
Laboratory and office equipment	5 years
Computers and software	3 years
Furniture and fixtures	7 years
Building	30 years
Leasehold improvements	Shorter of life of lease or 10 years

Non-employees

Recently Adopted Accounting Pronouncements

Schedule of assumptions used to determine the fair value of stock awards granted

Risk-free interest rate		2.3	%
Expected volatility		74	%
Expected dividend yield		—
Expected term (in years)		6.1
Common stock value	$	6.28

ASU 2018-07

Recently Adopted Accounting Pronouncements

Summary of impact of accounting standard adoption

The following table summarizes the cumulative effect to the Company’s consolidated balance sheet upon the adoption of ASU 2018-07 on January 1, 2018 (in thousands):

	Balance at				Balance at
	December 31, 2017		Adjustments		January 1, 2018
Additional paid-in capital	$	17,277	$	(92)	$	17,185
Accumulated deficit		(60,979)		92		(60,887)

Schedule of assumptions used to determine the fair value of stock awards granted

	Year ended December 31,
	2017
Risk-free interest rate	2.02% - 2.31%
Expected volatility	74% - 85%
Expected dividend yield	—
Expected term (in years)	6 - 10
Fair value of common stock	$0.19 - $6.28

ASU 2016-02

Recently Adopted Accounting Pronouncements

Summary of impact of accounting standard adoption

The following table summarizes the financial impact on the Company’s consolidated balance sheet upon the adoption of ASU 2016-02 and the cumulative effect adjustment on January 1, 2019 (in thousands):

	Balance at				Balance at
	December 31, 2018		Adjustments		January 1, 2019
Operating lease, right-of-use-asset	$	—	$	1,751	$	1,751
Property, plant and equipment, net		62,796		(45,142)		17,654
Deferred rent		143		(143)		—
Accrued expenses and other current liabilities		12,118		(4,451)		7,667
Lease financing obligation		41,441		(41,441)		—
Operating lease liabilities		—		616		616
Operating lease liabilities, net of current portion		—		1,226		1,226
Accumulated deficit		(150,082)		800		(149,282)