Balance at

Beginning of

End of

Year Ended December 31, 2020

Period

Additions

Deductions

Period

Contract assets:

Receivable from collaboration partner - related party

$

5,955

$

6,221

$

(9,750)

$

2,426

Contract asset - related party

$

800

$

342

$

(1,142)

$

—

Contract liabilities:

Deferred revenue - related party

$

41,530

$

3,963

$

(31,016)

$

14,477

Payable to collaboration partner - related party

$

1,262

$

3,800

$

(2,330)

$

2,732

Balance at

Beginning of

End of

Year Ended December 31, 2019

Period

Additions

Deductions

Period

Contract assets:

Receivable from collaboration partner - related party

$

2,042

$

36,837

$

(32,924)

$

5,955

Contract asset - related party

$

2,545

$

800

$

(2,545)

$

800

Contract liabilities:

Deferred revenue - related party

$

8,223

$

42,456

$

(9,149)

$

41,530

Payable to collaboration partner - related party

$

1,061

$

1,468

$

(1,267)

$

1,262