Stock-Based Awards (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Sep. 15, 2015	Aug. 25, 2015
Stock-based awards
Options granted (in shares)	1,238,262	500,262
Number of Shares
Number of Shares, beginning balance	500,262
Number of Shares, Granted	1,238,262	500,262
Number of Shares, ending balance	1,738,524	500,262
Number of Shares, Options vested and expected to vest	1,738,524
Number of Shares, Options exercisable	147,672
Weighted Average Exercise Price
Weighted Average Exercise Price, beginning balance (in dollars per share)	$ 1.22
Weighted Average Exercise Price, Granted (in dollars per share)	18.08	$ 1.22
Weighted Average Exercise Price, ending balance (in dollars per share)	13.23	$ 1.22
Weighted Average Exercise Price, Options vested and expected to vest (in dollars per share)	13.23
Weighted Average Exercise Price, Options exercisable (in dollars per share)	$ 1.19
Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term (in years)	9 years 6 months 4 days	9 years 9 months 7 days
Weighted Average Remaining Contractual Term, Options vested and expected to vest (in years)	9 years 6 months 4 days
Weighted Average Remaining Contractual Term, Options exercisable (in years)	8 years 8 months 19 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value	$ 24,722	$ 305
Aggregate Intrinsic Value, Options vested and expected to vest	24,722
Aggregate Intrinsic Value, Options exercisable	$ 3,803
Weighted average grant-date fair value of stock options granted (in dollars per share)	$ 13.84	$ 1.38
Employee, director and consultant stock options
Stock-based awards
Options granted (in shares)			0
Stock Option Valuation
Risk-free interest rate (as a percent)	1.78%	1.87%
Expected term (in years)	6 years 3 months 18 days	6 years 4 months 24 days
Expected volatility (as a percent)	93.90%	113.90%
Expected dividend yield (as a percent)	0.00%	0.00%
Expected forfeiture rate (as a percent)	0.00%	0.00%
Number of Shares
Number of Shares, Granted			0
2012 Equity Compensation Plan
Stock-based awards
Number of shares authorized		500,262			1,539,169
Number of shares available for grant	0
2012 Equity Compensation Plan | Maximum
Stock-based awards
Term of award (in years)	10 years
2012 Equity Compensation Plan | Employee, director and consultant stock options
Stock-based awards
Exercise price as percentage of fair market value of common stock at grant date required, minimum	100.00%
Term of award (in years)	10 years
Vesting period (in years)	4 years
2015 Equity Incentive Plan
Stock-based awards
Number of shares authorized				2,784,395
Percentage increase to shares available for grant from common outstanding as of preceding December 31 (as a percent)				4.00%