Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended	6 Months Ended
	Mar. 20, 2014	Jan. 13, 2014	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Common stock reserved for issuance upon exercise of outstanding common stock options and vesting of restricted stock units			1,793,349	1,793,349
Common stock reserved for future grants of stock options			2,279,933	2,279,933
Common stock reserved for future exercise of outstanding warrants			267,826	267,826
Issue of common stock shares	2,875,000	3,047,500
Number of shares sold pursuant to full exercise of underwriter's over allotment option	375,000	397,500
Exercise price of shares	$ 13.00	$ 10.65
Gross proceeds from public offering	$ 4,900	$ 32,500
Net proceeds from public offering	4,400	30,300
Underwriting of Discount and expense	319	$ 2,300
Estimated costs of public offering	$ 148
Common stock warrants outstanding			267,826	267,826	267,826
Common stock warrants exercised			0	0