Stock Option Plan - Summary of Stock Option Plans Activity (Details) (USD $)	1 Months Ended		3 Months Ended		12 Months Ended
	Mar. 31, 2014	Jan. 31, 2014	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Beginning Balance			595,577
Number of Shares, Granted	249,361	2,094	0	251,455
Number of Shares, Exercised			(1,149)
Number of Shares, Forfeited			(765)
Number of Shares, Ending Balance			593,663		595,577
Number of Shares, Vested and expected to vest			583,536
Number of Shares, Exercisable			324,189
Weighted-Average Exercise Price Per Share, Beginning Balance			$ 3.71
Weighted-Average Exercise Price Per Share, Granted	$ 2.15	$ 2.15
Weighted-Average Exercise Price Per Share, Exercised			$ 4.32
Weighted-Average Exercise Price Per Share, Forfeited			$ 8.65
Weighted-Average Exercise Price Per Share, Ending Balance			$ 3.70		$ 3.71
Weighted-Average Exercise Price Per Share, Vested and expected to vest			$ 3.69
Weighted-Average Exercise Price Per Share, Exercisable			$ 3.39
Weighted-Average Remaining Contractual Life, Outstanding			7 years 9 months 18 days		6 years 4 months 24 days
Weighted-Average Remaining Contractual Life, Vested and excepted to vest			7 years 8 months 12 days
Weighted-Average Remaining Contractual Life, Exercisable			6 years 3 months 18 days
Aggregate Intrinsic Value, Ending Balance			$ 6,114,729
Aggregate Intrinsic Value, Vested and expected to vest			6,016,256
Aggregate Intrinsic Value, Exercisable			$ 3,439,645