Reverse Merger - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Mar. 22, 2016	Dec. 31, 2016	Dec. 31, 2015
Reverse Merger Transactions [Line Items]
Combined shares of common stock outstanding		8,356,659	273,993
Estimated fair value of assets	$ 27,347
Reverse Stock Split [Member]
Reverse Merger Transactions [Line Items]
Common stock exchange price per share	$ 0.09
Combined shares of common stock outstanding	6,945,401
Celladon Europe [Member]
Reverse Merger Transactions [Line Items]
Combined shares of common stock outstanding	1,596,959
Percentage of shares acquired by share holders of Celladon	22.00%
Market capitalization	$ 27,500
Estimated fair value of assets	$ 27,300
Eiger BioPharmaceuticals, Inc [Member]
Reverse Merger Transactions [Line Items]
Percentage of shares acquired by stock holders, warrant holders and option holders after merger	78.00%
Reverse Merger [Member]
Reverse Merger Transactions [Line Items]
Date of acquisition		Mar. 22, 2016
Reverse Merger [Member] | Celladon Europe [Member]
Reverse Merger Transactions [Line Items]
Ownership percentage	78.00%