Acquisition and Stockholders' Equity (Deficit) (Details 5) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended		2 Months Ended	3 Months Ended	10 Months Ended	0 Months Ended
	Feb. 06, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 05, 2014	Jun. 21, 2012	Mar. 04, 2014	Dec. 31, 2012	Dec. 31, 2014	Jan. 28, 2014	Feb. 05, 2014
Acquisition and Stockholders' Equity (Deficit)
Decrease in exercise price (in dollars per share)	$ 0.011
Common stock, par value (in dollars per share)		$ 0.0001	$ 0.0001		$ 0.0001				$ 0.0001
Gross proceeds from sale of common stock by the entity (in dollars)		$ 30,700,000	$ 94,734,000	$ 55,862,000
Fees and expenses associated with offering		846,000	5,623,000	3,774,000
Proceeds from exercise of stock options		36,000	119,000
June 2012 Amended Controlled Equity Offering Sales Agreement
Acquisition and Stockholders' Equity (Deficit)
Additional aggregate offering price of common stock					50,000,000
Common stock issued (in shares)		6,417,450	758,093				3,644,143	815,654	2,773,507
Gross proceeds from sale of common stock by the entity (in dollars)		30,700,000	4,700,000				21,200,000	4,111,802	9,500,000
Average selling price (in dollars per share)			$ 6.16				$ 5.82	$ 5.04	$ 3.42
Maximum share amount to be issued and sold under agreement						30,000,000	30,000,000
Fees and expenses associated with offering								$ 123,385	$ 846,238
ContraVir Subsidiary
Acquisition and Stockholders' Equity (Deficit)
Shares approved for distribution										9,000,000
Shares of subsidiary to be distributed for each share of the entity's shares outstanding										0.0986
Public Company
Acquisition and Stockholders' Equity (Deficit)
Warrants outstanding (in shares)		5,647,203							5,647,203
Public Company | Weighted average
Acquisition and Stockholders' Equity (Deficit)
Exercise price of warrants (in dollars per share)		$ 5.383							$ 5.383		$ 5.395