Commitments and Contingencies - (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2018
Other Commitments [Line Items]
Total		$ 28,165
2019		1,416
2020		1,471
2021		23,439
2022		1,471
2023		368
2024 and thereafter		$ 0
Convertible Debt
Other Commitments [Line Items]
Period after product candidate FCX-007 is approved to reach maturity date	180 days	180 days
Operating lease obligations
Other Commitments [Line Items]
Total		$ 6,197
2019		1,416
2020		1,471
2021		1,471
2022		1,471
2023		368
2024 and thereafter		0
Debt obligations
Other Commitments [Line Items]
Total		21,968
2019		0
2020		0
2021		21,968
2022		0
2023		0
2024 and thereafter		$ 0