Ans Since you are Indian citizen and you did not stay for more than 181 days in a year , you saved yourself from being treated as Resident. If that would have been the case, all income of yours whether earned in India or USA would have been taxable in India. However, since you are Non Resident as per Income tax Act, your income is taxable in India if

   1. Any income is received in India
   2. Any income is deemed to be received in India
   3. Any income which accrues or arises in India
   4. Any Income which is deemed to accrue or arise in India[section 9(1)(vi)]

Since you are paid salary by USA based company and received your salary in USA , conditions 1,2,3 above are not satisfied.

As far as the last condition is concerned, there is specific provision for salary under section 9(1)(ii) which states that salary is deemed to accrue or arise in India "if it is earned in India." There is an explanation which declares that " income of the nature referred to in this clause payable for service rendered in India shall be regarded as income earned in India .This is a grey area and only judicial interpretation can clear the ambiguities . Plain reading of the Act shows that for the service rendered by you in India fro which you received salary should be treated as income earned in India and therefore even if you are non resident , same is taxable in India.So, prima facie' , your salary seems to taxable under I T Act.

The saving Grace!
However, there is Double Taxation Avoidance Agreement between India and USA which contains Article 16 related to dependent personal services which states that except in following condition the salaries ,wages or remuneration is taxable in the State where the employment is exercised . The conditions are given sub clause 2 of article 16 which is reproduced below :

    2. Notwithstanding the provisions of paragraph 1, remuneration derived by a resident of a Contracting State in respect of an employment exercised in the other Contracting State shall be taxable only in the first-mentioned State, if :
    (a) the recipient is present in the other State for a period or periods not exceeding in the aggregate 183 days in the relevant taxable year ;
    (b) the remuneration is paid by, or on behalf of, an employer who is not a resident of the other State ; and
    (c) the remuneration is not borne by a permanent establishment or a fixed base or a trade or business which the employer has in the other State"

I find from the facts narrated by you , conditions 2(a) and 2(b) is definitely satisfied as you were not in India for more than 180 days in any one financial year and remuneration is paid by your employer which is not a resident of India. The third condition , you will have to check ,if your salary was borne by the permanent establishment (subsidiary) of your company in India . If Indian office of your company did not bear the salary paid to you , then DTAA protects you from being taxed in India. You should also be aware that it is legally settled that DTAA supersede I.T Act . For more on this read this article.