Commitments and contingencies (Tables)

12 Months Ended

Mar. 31, 2015

Commitments And Contingencies Disclosure [Abstract]

Operating Lease Expenses Included in Determination of Net Income [Table Text Block]

Operating lease expense that has been included in the determination of the net income is as follows:

	Years ended March 31,
	2013		2014		2015
	US$		US$		US$
Office premises		726,893		700,402		668,676
Residential apartments for employees		104,557		81,308		81,980
Total operating lease expense		831,450		781,710		750,656

Schedule Of Future Minimum Rental Payments For Operating Leases [Table Text Block]

The minimum annual lease commitments under the above operating leases that have initial or remaining terms in excess of one year are as follows:

For the year ending March 31,	US$
2016		492,935
2017		293,624
2018		237,989
2019		40,753
2020		—