Stockholders' Equity - Summary of the Company's Stock Option Activity under its 2005 and 2015 Plans (Detail) - Jun. 30, 2015 - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Total
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options Available for Grant, Beginning Balance	54
Options Available for Grant, Options granted	(1,423)
Options Available for Grant, Options forfeited	190
Options Available for Grant, Options expired	(60)
Options Available for Grant, Options authorized	4,000
Options Available for Grant, Ending Balance	2,761
Options Outstanding, Beginning Balance	672
Options Outstanding, Options granted	1,423
Options Outstanding, Options forfeited	(190)
Options Outstanding, Options expired	0
Options Outstanding, Ending Balance	1,905
Options Outstanding, Exercisable, Ending Balance	493
Options Outstanding, Vested and expected to vest, Ending Balance	1,322
Weighted Average Exercise Price, Beginning Balance	$ 3.63
Weighted Average Exercise Price, Options granted	1.44
Weighted Average Exercise Price, Options forfeited	1.93
Weighted Average Exercise Price, Options expired	2.67
Weighted Average Exercise Price, Ending Balance	2.16
Weighted Average Exercise Price, Exercisable, Ending Balance	3.28
Weighted Average Exercise Price, Vested and expected to vest, Ending Balance	$ 2.39
Weighted Average Remaining Contractual Life, Beginning Balance	8 years 5 months 27 days
Weighted Average Remaining Contractual Life, Ending Balance	8 years 9 months 11 days
Weighted Average Remaining Contractual Life, Exercisable, Ending Balance	8 years 1 month 6 days
Weighted Average Remaining Contractual Life, Vested and expected to vest, Ending Balance	8 years 6 months 4 days
Aggregate Intrinsic Value, Ending Balance	$ 0
Aggregate Intrinsic Value, Exercisable, Ending Balance	0
Aggregate Intrinsic Value, Vested and expected to vest, Ending Balance	$ 0