Stockholders' Equity - Additional Information (Details) - USD ($)			1 Months Ended	3 Months Ended			6 Months Ended
	Feb. 21, 2017	Dec. 23, 2013	May 31, 2016	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	May 01, 2016	Feb. 28, 2014
Class of Stock [Line Items]
Common stock, shares authorized				175,000,000			175,000,000		175,000,000
Common stock, par value				$ 0.00001			$ 0.00001		$ 0.00001
Common stock, shares issued				42,490,957			42,490,957		38,615,709
Common stock, shares outstanding				42,490,957			42,490,957		38,615,709
Preferred stock, shares authorized				25,000,000			25,000,000		25,000,000
Preferred stock, par value				$ 0.00001			$ 0.00001		$ 0.00001
Preferred stock, shares issued				0			0		0
Preferred stock, shares outstanding				0			0		0
Common stock, shares reserved for future issuance				6,783,823			6,783,823		5,268,127
Stock-based compensation expense				$ 2,505,000		$ 1,222,000	$ 7,933,000	$ 2,473,000
Restricted Stock Units
Class of Stock [Line Items]
Granted shares of restricted stock	423,650
Vesting periods							3 years
Stock-based compensation expense				659,000		158,000	$ 1,050,000	264,000
Total compensation cost to be recognized				2,900,000			$ 2,900,000
Restricted Stock Units | Share Based Compensation Award Tranche One
Class of Stock [Line Items]
Vesting percentage							100.00%
Stock Options
Class of Stock [Line Items]
Shares issued	719,400
Stock-based compensation description							Options granted by the Company vest over periods of between 12 and 48 months, subject, in each case, to the individual’s continued service through the applicable vesting date. Options vest in installments of (i) 25% at the one year anniversary and (ii) in either 36 or 48 equal monthly or 12 equal quarterly installments beginning in the thirteenth month after the initial vesting commencement date or grant date, subject to the individual’s continuous service with the Company.
Options expiration after the date of grant							10 years
Stock-based compensation expense				1,747,000		1,021,000	$ 3,322,000	2,149,000
Stock Options | Minimum
Class of Stock [Line Items]
Vesting periods							12 months
Stock Options | Maximum
Class of Stock [Line Items]
Vesting periods							48 months
Stock Options | Share Based Compensation Award Tranche One
Class of Stock [Line Items]
Vesting percentage							25.00%
Restricted Stock
Class of Stock [Line Items]
Vesting periods		1 year
Stock-based compensation expense				57,000		27,000	$ 65,000	13,000
Granted, Weighted-Average Grant Date Fair Value		$ 7.42
Restricted stock requisite service period description							The awards of restricted stock contained a performance condition wherein vesting is contingent upon the Company’s consummation of a liquidity event, as defined, prior to the fifth anniversary of the date of grant. Certain of the awards of restricted stock have a requisite service period that was complete upon grant. The remainder of the awards of restricted stock have a requisite service period of four years whereby the award vests 25% on the one year anniversary of the Vesting Commencement Date (as defined), then ratably on the first day of each calendar quarter for 12 quarters, subject to continuous service by the individual and achievement of the performance target.
Grant-date fair value of restricted stock issued		$ 3,900,000
Award requisite service period		4 years
Restricted Stock | Share Based Compensation Award Tranche One
Class of Stock [Line Items]
Vesting percentage		25.00%
Restricted Stock | Employees
Class of Stock [Line Items]
Granted shares of restricted stock		450,224
Restricted Stock | Non Employees
Class of Stock [Line Items]
Granted shares of restricted stock		79,067
Stock-based compensation expense				$ 49,000		27,000	$ 100,000	13,000
2014 Plans
Class of Stock [Line Items]
Common stock, shares reserved for future issuance				739,579			739,579		885,328		1,785,000
Incremental rate at which the shares reserved for issuance increase							3.00%
2014 Plans | Employees
Class of Stock [Line Items]
Granted, Shares							1,043,900
2014 Plans | Director
Class of Stock [Line Items]
Granted, Shares							87,500
2014 Plans | Inducement Award Program
Class of Stock [Line Items]
Common stock, shares reserved for future issuance										350,000
Granted, Shares			255,000
2014 Plans | Inducement Award Program | Employees
Class of Stock [Line Items]
Granted, Shares							324,500
2014 Plans | Restricted Stock Units | Employees
Class of Stock [Line Items]
Granted shares of restricted stock							439,900
2014 Employee Stock Purchase Plan
Class of Stock [Line Items]
Maximum shares of common stock authorized to be issued				262,500			262,500
Percentage of increase on common stock authorized on each anniversary							1.00%
Number of common stock outstanding							739,611
Common stock shares authorized percentage under the plan							5.00%
Purchase price at the end of offering period							85.00%
Offering period							6 months
Shares issued					19,317
Stock-based compensation expense				$ 42,000		$ 16,000	$ 100,000	$ 47,000