Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Changes in fair value (Detail)

v3.19.1
Fair Value Measurements - Changes in fair value (Detail) - Caelum [Member]
$ in Thousands
3 Months Ended
Mar. 31, 2019
USD ($)
Balance $ 10,905
Conversion of convertible notes (9,914)
Issuance of warrant (991)
Balance 0
Warrant [Member]  
Balance 991
Conversion of convertible notes 0
Issuance of warrant (991)
Balance 0
Caelum Convertible Notes [Member]  
Balance 9,914
Conversion of convertible notes (9,914)
Issuance of warrant 0
Balance $ 0