Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	Mar. 20, 2014	Jan. 13, 2014	Dec. 31, 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			3,305,589
Common stock reserved for future grants of stock options and restricted stock units			732,270
Common stock reserved for future exercise of outstanding warrants			24,380
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		$ 34,957
Net proceeds from public offering	4,400	30,300
Underwriting of Discount and expense	319	$ 2,300
Estimated costs of public offering	$ 148
Outstanding warrants to purchase common stock			24,380	267,826
Outstanding warrants to purchase common stock at exercise price per share			$ 3.65	$ 3.65
Warrants exercisable date of issuance			10 years
Number of warrants expired			243,336
Repurchase of company shares			0	0