9. STOCK- BASED COMPENSATION - Stock options activities (Details) - USD ($)	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Stock-Based Compensation
Shares available for grant, Beginning	6,213,943	5,585,500	4,867,458
Options reserved (in shares)	1,156,419	1,377,699	1,353,260
Granted (in shares)	(969,913)	(791,903)	(784,303)
Forfeited/expired (in shares)	31,614	42,647	149,085
Shares available for grant, Ending	6,432,063	6,213,943	5,585,500
Number of Shares Underlying Options Outstanding
Balance at the beginning of the period (in shares)	6,774,151	6,143,980	6,336,319
Granted (in shares)	969,913	791,903	784,303
Exercised (in shares)	(76,745)	(119,085)	(816,957)
Forfeited (in shares)	(41,614)	(42,647)	(159,685)
Balance at the end of the period (in shares)	7,625,705	6,774,151	6,143,980
Options vested and exercisable (in shares)	5,246,088
Options vested and expected to vest (in shares)	7,574,414
Weighted Average Remaining Contractual Life
Options vested and exercisable	3 years 8 months 12 days
Options vested and expected to vest	5 years 1 month 21 days
Weighted Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 5.16	$ 5.13	$ 4.46
Granted (in dollars per share)	4.42	5.20	6.45
Exercised (in dollars per share)	4.19	3.88	3.10
Forfeited (in dollars per share)	4.82	5.49	6.04
Balance at the end of the period (in dollars per share)	5.08	$ 5.16	$ 5.13
Options vested and exercisable (in dollars per share)	5.02
Options vested and expected to vest (in dollars per share)	$ 5.08
Intrinsic Value
Exercised (in dollars)	$ 46,977	$ 262,253	$ 2,629,982
Options vested and exercisable (in dollars)	939,846
Options vested and expected to vest (in dollars)	$ 1,150,077